Caitlin Walker was spending time with her two sons, two-year-old Oakley and and five-month old Aston at the back of their Ballarat home about 12.45pm on Thursday, February 29, when she heard a commotion around the corner on the grass.

"I was inside doing some washing and I had my youngest son on the ground playing and my oldest son sitting on a chair outside picking some strawberries for himself ... I could see him through the door," Ms Walker said.

"I could hear my dog Nala barking outside, and she kept barking. I just thought she was barking at a piece of plastic like she normally does, so I picked Aston up and and took him outside to check on Oakley.

"As I picked him up, I walked out the door to see what Nala was barking at and I turned my head around the corner and she was grabbing a snake.

"The snake started to come up onto the decking."

It was then Ms Walker made a split-second decision that no-doubt saved her oldest son from danger - with the whole incident captured on a security camera and lasting less than two minutes.

The footage shows the 29-year-old instantly turning around at the sight of the dog and snake - estimated to be about 1.2 metres in length - and running inside to get Aston to safety before running back onto the decking to get Oakley, who was sitting in a chair about three metres away.

"I thought, 'I've got to try and get two kids inside with this snake that's moving quick'. It was terrifying," she said.

"I ran back to the sliding doors and put Aston on the ground carefully, but quickly.

"I'm glad I shut the door behind me because as I've gone to grab Oakley I've jumped over the snake - it was right next to my feet at the door."

After picking up Oakley from where he was sitting, Ms Walker said as she attempted to run back to the safety of inside the house, she realised the snake and the dog were blocking the door.

"If I hadn't have shut the door they would have gone inside the house," she said.

The snake, in an attempt to escape to safety itself, moved under some play equipment and right underneath the seat where Oakley was sitting just moments earlier.

"I grabbed Oakley, ran to the laundry door outside and realised I'd locked the laundry door and the garage door ... and the gate to the front of the house was locked as well," Ms Walker said.

"I put Oakley up onto the camper trailer then I jumped onto the camper trailer. I saw Nala head towards the back of the fence ... I'm surprised the snake did not bite her, it had multiple cracks at her ... I think that's why she was barking at it for a while.

"I don't think Nala wasn't attacking the snake, she was just curious and trying to play with it.

"I think it's gone at her and she's like 'oh, let's play', and she's just thought this is a playing thing ... I could hear it hissing at her."

Once the snake made it to a garden bed and Ms Walker had a clear path inside, she got Oakley and herself to safety and called her husband Josh on the phone.

"Nala's collar broke the other day and we're waiting on another to arrive, so I didn't have anything to grab her with to bring her back inside. When she's got something new to play with she doesn't listen to me, she won't come inside," she laughed.

"Josh called our friend Bryce who lives across the road and he ran here like The Flash and got Nala. Thank god she was safe, I put her in the garage and checked her out - she had no bites that I could see, she was fine for the rest of the day.

"My heart finally slowed down."

Ms Walker said it could have been a different story if her son was sitting at the sand table, where he normally likes to play.

"It was just a split second 'grab the child and get inside' moment, especially because Oakley has been obsessed with snakes lately ... I was worried he would think it was a toy and want to play with it," she said.

Ms Walker said she shared the CCTV video with her family and friends who "all laughed".

"I don't think they've ever seen me run so quickly either," she said.

"Everyone was concerned about the dog. We rely on her now to figure out if there's a snake in our backyard because she will go and find it first."

It's not the first time a snake has caught Nala's curiosity. Just two weeks before this incident, another copperhead was found sleeping between two garden beds in the backyard, but luckily the children were safe in bed and asleep.

"It's obviously something we didn't expect to see in a suburban estate," Ms Walker said.

"We've happened to have seen two in two weeks and we've lived her for five years.

"It's the only time we've ever seen them."

In both instances, the Walker family called snake catchers who were able to safely relocate both snakes away from the property.

They're now in the process of snake proofing their backyard, which backs onto a large paddock on the southern side - where stage two of the Ballarat Link Road is slated to be built.

Their house is also not far from a large wetland area in the estate.

In 2023, snake catcher and Monash University research officer Jules Farquhar said copperheads were a live-bearing snake that liked slightly higher altitude and cooler climate.

He said copperheads were more commonly found around open wetland residential areas, as they ate small lizards and frogs.