Wollongong Police Chief Inspector Graeme Donnelly said officers would maintain a high profile at the protest, aimed at stopping the expansion of the Metropolitan Colliery.

Protest organisers had sought permission to march through the main street of Helensburgh, but Insp Donnelly today said negotiations over the route were continuing.

"We obviously have to take the public interest and safety into consideration before approving a route," he said.

The three-day camp includes workshops and demonstrations that organisers say are aimed at protecting water catchments from damage and pollution by coal mining.

At the inaugural Australian Climate Camp in Newcastle last year, six activists were arrested for blocking a coal train.

Last week Wollongong local area commander Superintendent Kyle Stewart warned protesters heading to the camp to stay within the law or face arrest.

Event organisers had assured him the majority wanted to get their message across lawfully, he said.

"Police will not tolerate militant protesters hijacking the event, while those displaying drunken, loutish or antisocial behaviour will also be given little latitude," he said.