A NSW woman was returning home after taking her three daughters - all of whom have autonomic dysfunction  - to see a specialist in Melbourne when she left her handbag containing jewellery worth $30,000 at a public toilet. 

Detective Senior Constable Jason Smith said the woman's daughters are required to attend appointments with specialists in the city on a regular basis.

He said the woman, who lives on the NSW border, decided to take the opportunity to get the jewellery valued and cleaned.

He said the woman's mind was preoccupied when she accidentally left her handbag in a toilet at Marong in April.

"She has three daughters who suffer from the same illness, from 20 down to 14 years of age," he said. 

"For her, her focus is her daughters and always has been.

"That is probably why her mind was on them and (not on her handbag).

"It's really easy to put something down and walk away, and that's what has happened on this occasion."

Detective Senior Constable Smith said the jewellery held sentimental value for the woman.  

"Some of the jewellery is heirloom jewellery," he said. 

"So it does hold sentimental value as well as a monetary value." 

Anyone with information about the jewellery should contact Crime Stoppers on 1800 333 000 or Bendigo Police on 5448 1360.  

TUESDAY: 

Police are calling for information on the theft "very distinctive" jewellery worth $30,000 left at a public toilet at Marong in April.

Detective Senior Constable Jason Smith of Bendigo Criminal Investigative Unit said the jewellery, consisting of five main items, was stolen from a handbag left in a Marong public toilet on April 29.

The owner of the handbag, a woman from NSW, had been driving through regional Victoria from Melbourne, where she had visited to have the jewellery repaired and valued, when she stopped in Marong.

Detective Senior Constable Smith said the woman did not realise she had left her bag in the toilet until she reached Serpentine.

He said the woman received a call on her mobile from another woman at 5.20pm indicating she had found the handbag, but minus the jewellery.

Detective Senior Constable Smith said a police report was filed later that day, but police investigations since April 29 had not revealed many clues as to the jewellery's whereabouts.

"There is an ongoing investigation in relation to establishing what happened to the jewellery," he said.

"We've exhausted many avenues of investigation at this time and are seeking public help for information about the theft."

Detective Senior Constable Smith said the theft was in an isolated area and there was "not a lot to go on".

"But the jewellery was very distinctive and would be very identifiable," he said.

Among the jewellery items stolen were a 14K white gold tennis bracelet with blue topaz and diamonds, a platinum ladies diamond ring, 14K white gold sapphire and diamond Ring, a 1912 Gold Sovereign made into pedant on a gold chain, a 14K white gold necklace with blue/violet tanzanite and pendant containing mid blue/violet  and two gold rings with gold bands.

Anyone with information is urged to contact Crime Stoppers on 1800 333 000 or the Bendigo CIU on 5440 2545.