Owners in a retail strip along the South Gippsland Highway in Cranbourne say the council has threatened them with fines when they put up signage or other promotional items outside their businesses.

Foord's Mower Mart owner Hans Isarin said he encountered problems when he parked lawnmowers outside to advertise his business.

"We do the same at our shop in Keysborough and it's never been a problem.

"Now that I can't put them out, I get customers always asking where we are. It affects our business."

The newly opened Kilgerron Homestead in Narre Warren South was not allowed to put an advertising sign at its Narre Warren-Cranbourne Road entrance.

Owner Ruby Verberne said the land was owned by VicRoads, and a sign would require her to enter into a lease agreement with the road authority.

That was not a viable option, and Ms Verberne said she was able to erect signs within the homestead's property boundary.

Casey planning manager Duncan Turner said business advertising signage was regulated by state planning legislation, which the council was required to enforce.

He said a certain amount of signage could be erected without a planning permit, but if a business owner wished to exceed that, a permit was needed.

"When considering permits, the council takes into account the need to ensure the community is not subjected to a proliferation of advertising signage, which becomes an eyesore."

Mr Turner said the lawnmowers at Foord's Mower Mart had posed a risk to the public as they had been placed on top of bollards.