Arrests over car theft with toddler inside

Two men have been arrested after a car was stolen with a toddler asleep in the back seat in Melbourne's southeast.

The two-year-old boy was alone in the car with the engine still running while his father went into a shop on Nepean Highway in Chelsea at 4pm on Sunday.

Police say a thief then snuck into the grey Volkswagen SUV and took off.

The car stopped about 350 metres away and the child was left by the side of a road.

A passerby found him distressed but unharmed a short time later.

A Narre Warren man, 18, and a Clarinda man, 20, were arrested at a shopping centre in Frankston just after midday on Tuesday.

They are said to be assisting police and the investigation is ongoing.

The stolen car has not been found.

On Monday, Victoria Police said the father left his son alone for a few minutes with the air conditioning on and ruled out laying any charges against him because it was not in the public's interest.