Warrnambool police Sergeant Bec Miles said members were actively checking on guests and their reasons for being in town.

It comes as metropolitan Melbourne and Mitchell Shire residents deal with stage three restrictions, brought in last week for a period of six weeks, to help contain the coronavirus spread.

"If people are thinking they can get away with it because there are no road blocks set up, think again," Sergeant Miles said.

"If people already had a holiday booked here when the new rules came in they can continue their stay but they're not allowed to extend that stay.

"We are also double checking the reasons people say they were staying; if you say you're down here working at the gas plant and that's found to be false, you are liable for a fine.

"If you are not here for the four legitimate reasons then you are not allowed here."

Camperdown police were tasked with inspecting accommodation providers on Sunday and Leading Senior Constable Adam Johnston said everyday, somewhere in the region, police would be checking on tourists.

"It's one of the routine tasks now and we have been going around but hadn't found anyone in breach of the restrictions," he said.

"What we do is inspect vehicles and registrations at accommodation providers and if that registration is to somewhere in Melbourne or Mitchell Shire then make further inquiries.

"If people were already on holidays prior to the lockdown restrictions, then there is no requirement to return home."

Around five south-west police members are assisting at border checks near Melbourne.

Anyone from metropolitan Melbourne or Mitchell Shire caught breaching the four reasons to leave their postcode will be issued with a $1652 fine.

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