Pregnant worker threatened in robbery

A heavily pregnant woman has been threatened and robbed while working in a Victoria service station.

A man entered the Sunbury station, northwest of Melbourne, as the woman, eight months pregnant, was closing up on Wednesday night.

He demanded cash but was unhappy with the amount he received and told the woman he had a gun and threatened her.

The man left when the woman told him she'd given him all the cash.

Police are looking for the man, who is thought to be in his 20s with a solid build and crew cut.

He was wearing a grey jumper and grey tracksuit pants.

The woman was not injured.