UPDATE 7.30pm: The father of the toddler found dead in a car outside a Kyneton childcare centre has paid tribute to his son and urged parents to hug their children.

The circumstances surrounding the death of the 22-month-old in the central Victorian town on Thursday afternoon remain unclear, homicide squad detectives said. 

His father posted tributes on social media on Friday, saying that the family had lost their "beautiful son".

"I love him more everyday, forever," he wrote.

"I'll always know I cherished every day, every laugh, every adventure, every cuddle."

"Hug your children and never let them go."

Earlier, police said the car in which the boy was found outside a Kyneton childcare centre had only been parked for a few minutes before he was found.

The mother of the boy, too distraught to be interviewed, was present when the child was found very shortly after the Toyota HiLux had parked outside the Acacia Drive home where the centre operated from, police said.

"The mother was present when the young boy was located and she's absolutely devastated by what's occurred," Detective Senior Sergeant O'Connell said.

UPDATE 2.37pm: Police have yet to speak with the mother of the boy because she is too distraught over his death, Homicide Squad Detective Senior Sergeant Shane O'Connell told media this afternoon.

"The mother was present when the young boy was located and she's absolutely devastated by what's occurred," Senior Sergeant O'Connell said.

"At this stage we haven't been able to establish what's happened. That's primarily because the mother is quite devastated and she hasn't been in the position to talk to us."

Senior Sergeant O'Connell said police found the boy's "equally devastated" father and brought him to Kyneton.

He said the car in which the boy was found had only been parked at the Kyneton daycare centre for a few minutes before he was found.

Senior Sergeant O'Connell said he was not sure if the car had been at the business, a registered daycare, earlier in the day.

Police also seized CCTV footage from cameras at a nearby house in the hope it may help them understand what happened.

The boy had a sibling and lived in the area with his family, police said.

Victoria Police has also released a statement saying detectives are awaiting the results of an autopsy and the exact cause of the boy's death is yet to be determined. 

Anyone with any information is urged to contact Crime Stoppers on 1800 333 000 or submit a confidential report at www.crimestoppersvic.com.au 

UPDATE 11.30am: The daycare business where a toddler was found dead in a car parked outside was a privately run, informal operation for families in the central Victorian town.

A young woman, the daughter of a successful local businessman, runs the daycare from the Acacia Drive home in Kyneton, caring for about six or seven children at a time, according to neighbours.

The woman's father said his daughter was distraught and wouldn't be talking to media. He said the family would issue a statement later on Friday.

Trevor and Trona D'Silva, who know parents who send their children to the daycare, say the young woman is trusted and well-liked.

Fairfax Media is not suggesting the young woman was responsible for the death of the 22-month-old boy, found in a car parked in the driveway at 3pm on Thursday.

"It's a community thing where everyone knows each other ... She'll be devastated because she loves kids, that's why she does that," Mrs D'Silva said.

Like many in the small, residential street that backs onto Kyneton's new hospital and ambulance station, the D'Silvas heard about the death only when a police officer knocked on their door.

"From that time forward we were deeply disturbed about what happened. We cannot believe, we cannot imagine, we cannot process the loss of this life," Mr D'Silva said.

A little further down the street Rob Wheeldon and his wife were still in shock.

"Everyone is really upset with what has happened. A street like this, everyone is really feeling for the family," Mr Wheeldon said.

Another local, Christine McKimm, came to the house to lay flowers on the letterbox.

Her daughter Charlotte, played nearby, blissfully unaware of the tragedy.

"The little boy that died isn't much older than my own daughter, and it's just something that's been on my mind since I saw the news last night," Christine said.

The death has hit the "real family community" hard, she said.

The Homicide Squad are leading the investigation into the death of the infant, who was found by a relative inside the sweltering car, reportedly still strapped into a baby seat in the back of the Toyota HiLux.

"It's not fair for me to pre-empt what may or may not have occurred," area commander Inspector Ryan Irwin said on Thursday.

"It's really early at this stage, there are a lot of sensitivities in relation to family members and other people who've had involvement with this event today," he said.

"Regardless of the circumstances, it's an absolute tragedy for the family and the other people living here."

Paramedics, who were called at 2.57pm, had to smash the back window of the car to gain entry.

They performed CPR for several minutes, but were unable to revive the boy.

The weather in Kyneton reached 31.6 degrees at 3pm. 

Previous Ambulance Victoria tests found that even on a 29-degree day the inside of a car can reach 44 degrees within 10 minutes, and 60 degrees within 20 minutes.

Its report, released on February 6, found there had been more than 200 cases of children being locked in cars during 2015 - an average of almost six a day. The vast majority of cases were in metropolitan Melbourne.

On February 10, firefighters had to smash the window of a car in Maribyrnong so paramedics could save a young girl who had been locked inside.

Despite the high number of children locked in cars, cases resulting in death are rare in Victoria.

It is believed the death on Thursday is the third since 2011.

It is also rare for police to charge individuals with manslaughter in relation to the deaths, with only three deaths resulting in criminal charges since 1992.

Two of those charged had knowingly left their child in the car.

The state government announced last August it intended to increase fines for leaving children in cars from $2214 to $3690 and double the maximum prison term to six months.

The government said at the time that 76 people had been sentenced for leaving children unattended - in houses, as well as cars - between 2010 and 2012.

It is unclear whether the new penalties were introduced, or whether the Andrews government intends to keep the measures.

KidSafe Victoria president Erica Edmands said most children are left in cars unintentionally, particularly after baby seats were designed to face backwards.

"You actually don't see the child and if they're asleep you don't see them, people don't see them," Ms Edmands said.

"For most people, it's not a deliberate act. Most people who find themselves in these situations are caring, loving parents who, for a few seconds, have done something and forgotten a child."

A Washington Post article, which won a Pulitzer Prize in 2010, found that cases of babies dying of hypothermia from being left in cars had increased substantially in the US since the early 1990s.

At that time, car-safety experts declared that passenger-side front air bags could kill children, and recommended that child seats be moved to the back of the car. It was then found that seats should be pivoted to face the rear and be placed behind the driver.

While this made children safer in a car accident, it was impossible for drivers to notice them in a rear vision mirror.

The article quoted a memory expert as saying that, despite public perception, parents whose children had died after being left in the car often had no history of poor parenting.

Kids and Cars, a US lobby group for increased car safety for children, have campaigned for all cars to contain sensors that would sound an alarm when the ignition was switched off but weight was detected on the rear seats of the car.

- The Age

EARLIER: A 22-month-old boy was found dead in a car in Acacia Drive in Kyneton on Thursday.

Police confirmed that the child was discovered by a family member at about 3pm.

Paramedics had to smash the rear window of the vehicle in an effort to reach the infant and performed CPR on the boy but were unable to revive him.

Local police and the homicide squad are investigating the death.

Macedon Ranges Inspector Ryan Irwin said the boy was a local and police were still trying to track down some family members on Thursday afternoon.

Inspector Irwin said the investigation was in its very early stages and police were pursuing a number of lines of inquiry.

He said the family was "absolutely devastated" by the tragic occurrence.

Inspector Irwin said investigators would keep an open mind while preparing a full report for the coroner.

"It is a warm day and that is something that's going to inform our inquires," he said.

"Regardless of the circumstances, this is an absolute tragedy for the family, the other people living in the area and for the emergency services who attended."

The temperature in Kyneton reached 31 degrees by 3pm.

The Toyota Hilux the child was in when it was discovered was one of a number of vehicles in the driveway of a house, which a neighbour said operated as a daycare centre, and police said all would be investigated.

Residents spoken to by the Bendigo Advertiser said their thoughts were with the child's family and that the incident would hit the community hard.

Midland Express reporter Chris Yeend told 3AW Drive word had already spread fast in the small country community.

"It's pretty devastating at the moment," he said.

"There are a lot of distraught residents nearby."

Macedon Ranges Shire mayor Jennifer Anderson told The Age it was always a tragedy when a little child died, but towns like Kyneton could feel it even more.

"People know people and it usually does effect the community, every time there's a tragedy," she said.

- with The Age, 3AW