According to the council, thousands of dollars' worth of road signs have been stolen from Port Fairy as works to build a new roundabout in Bank Street begin.

Moyne Shire director of infrastructure and environment Trevor Greenberger said the thefts were costly and dangerous.

"Council knows how strongly our residents feel about our road network," he said.

"We want to spend money on improving roads not wasting it on replacing signs.

"The thefts can also lead to accidents as road users rely on signage to warn them of dangers and changes to road conditions."

Mr Greenberger said police were investigating the thefts and security camera footage from nearby businesses had been found.

He urged residents to give Victoria Police assistance.