Years-long tensions between those opposed to the $9 million Princetown Eco Stay project and the developer came to a head as works started after the project was approved with conditions in 2017.

Police escorted Gavin Ronan, director of Montarosa Pty Ltd, off the premises on Monday after he accessed the site from the neighbouring Princetown Recreation Reserve.

The access was an alleged breach of one of the strict conditions of the planning permit.

Corangamite Shire Council mayor Ruth Gstrein said the council was assessing its legal options.

"There's a specific condition in the planning permit prohibiting that," she said. "Council will do further investigations and seek legal advice going forward and see how to take action."

There are 70 conditions on the planning permit, which was agreed upon by all parties.

The permit expires on Saturday.

Mr Ronan said there was a fence cut, which was repaired on Monday.

"Montarosa holds a validly issued planning permit," he said. "The only public road to the site was blocked by a protest, denying the landowner lawful access to their property.

"To be clear, the works are lawful, permitted and taking place on private property."

Warrnambool police Acting Inspector Brett Jackson said the protest was peaceful and the group would not be asked to move on "at this stage".