Police have released four people without charge after they refused to move from the Occupy Brisbane protest in Post Office Square in the city's centre.

The 18-day Occupy Brisbane protest is being dismantled in the square as police move on about 100 protesters.

Similar sit-ins have been staged in Australia and around the world, protesting against various issues, including corporate greed.

About 30 protesters have since relocated to nearby Queen's Park in the city.

Police said earlier today they would not arrest any protesters who had to be forcibly removed, unless they assaulted an officer.

Superintendent Brett Schapirius says a fence has been erected around the square as the protesters pack up their tents and belongings.

"Quite obviously we want a peaceful resolution to the events here," he said.

The Brisbane City Council says it needed to do work at the square and asked police to help move the protesters.

Brisbane Lord Mayor Graham Quirk says the protesters have had long enough to make their point.

"We have Remembrance Day coming up quite soon and that park of course is utilised for that purpose, so again I just say occupy Brisbane has had long enough now - they've made their statement," he said.

"We've given them time for peaceful assembly but the time has come they have to move on now.

"We have to get that park into the hands of all the people of this city."

Mr Quirk says ratepayers will foot the bill for the protest and that it will cost up to $30,000 to restore the square.

"In terms of restitution of those costs, it's virtually impossible to achieve, so that is something regretfully we'll be up for," he said.

"But it's time for that park to be handed back to the people of the city."

Police are now monitoring the protesters who have moved onto nearby Queen's Park, which is owned by the State Government.

Most complied with the police order to move on from Post Office Square, but protester Tom said earlier today activists should stay put.

"We think that people have a democratic right to protest against corporate greed," he said.

"We're part of a worldwide movement that's stretching all the way from Wall Street through to Rome through to Taiwan."

Fellow protester Rebecca remains defiant.

"We have every right to peacefully assemble in the streets of Brisbane and make a political protest and that's what we've been doing for the last 18 days," she said.

"We have every intention of continuing to defend that right this morning and we're aware of what that means."