A court injunction allowing police to arrest Algonquin protesters blocking the site of a potential uranium mine in eastern Ontario was formally served Friday afternoon, as required by a legal deadline.

The order that protesters have been anticipating arrived before 3:30 p.m. Friday, confirmed CBC Radio's JC Kenny from the scene.

A day earlier, Const. Paige Whiting of the Ontario Provincial Police, would not specify what action police planned to take after the order was served.

"We'll certainly be approaching it cautiously," she said.

Police met with protesters from the Ardoch and Shabot Obaadjiwan Algonquin First Nations Thursday to discuss what could happen in coming days at the protest camp near Sharbot Lake, about 60 kilometres north of Kingston, Ont.

There, protesters have installed a locked and guarded gate that bars entry to outsiders including Frontenac Ventures, a mining exploration company that wants to do test drilling for uranium at the site.

The protesters have occupied the site since late June, saying they fear uranium mining could pollute and damage their ancestral lands.

On Thursday, protesters could move freely in and out of the site, but that was expected to change shortly, said Robert Lovelace, former chief of the Ardoch First Nation.

Anyone coming onto site could be charged: Ardoch chief

"Once the injunction is served, they told us free movement in and out will no longer be permitted," Lovelace said. "Anyone coming out of the site would be subject to potential charges."

Police said non-aboriginal people who have been bringing medicine and food to the protesters could also be arrested for aiding in illegal movement.

On Thursday, the judge who granted the injunction met with Frontenac Ventures, but it was still unclear whether the company will be able to bring its equipment onto the site after the injunction is served.

The court order is the result of court action launched by Frontenac Ventures against the protesters, which includes a request for an injunction that would give them full access to the site as well as a lawsuit for $77 million in damages.