Police have defended using force to move Occupy Sydney protesters from Sydney's Martin Place during a dawn raid today.

Officers swooped just before 5:00am (AEDT) removing around 80 protesters from the square they had occupied for about a week in protest against corporate greed.

Protesters have criticised the police action, saying they were pinned down and man-handled by officers.

"I screamed, I was saying 'release the handcuffs, loosen the handcuffs my arm is going to break' - I said it over and over," one said.

"My arm was twisted behind my back and it felt like it was going to break and then dragged," said another.

But Assistant Police Commissioner Mark Murdoch says the group showed defiance by locking arms when police arrived.

"We encounter levels of resistance by the protesters; that resistance was met with a commensurate use of force," he said.

"If some people had their arms bent behind their backs I make no apologies for that. It was to ensure compliance and their own personal safety and the safety of my police."

He says the operation was conducted early in the morning for public safety reasons.

Mr Murdoch says the group had been relieving themselves in Martin Place, and abusing bankers on their way to work.

He says two protesters attacked police officers last night and will appear in court today charged with assault.

Forty protesters were arrested and some issued with fines for breaking council regulations

But Protester Time spokesman Davis Frank says the activists were peaceful.

"Seeing people who have been peaceful for eight days, crying and screaming in pain after they were woken up out of their sleep - it doesn't make any sense," he said.

Protester Amber Wallace says she was given just minutes to pack up before being moved.

"We didn't even get enough time to talk to our neighbour about what was going on," she said.

"They just did a conquer and divide - they got us while we were asleep. That was so completely unprovoked."

The group will meet again this afternoon at a university in Sydney. Police say they will be watching.

"We'll monitor that meeting this evening, and we will take action as appropriate," Mr Murdoch said.

"Police will be in Martin Place and around the city all day and all night, and all day and all night tomorrow. We will be vigilant to make sure what we have done today is not undone."

The Occupy Sydney protest started last week as part of the worldwide movement which began in New York against what protesters describe as corporate greed.

Melbourne protests

Meanwhile, Victorian Premier Ted Baillieu has praised police for their actions during the Occupy Melbourne protest.

Violence erupted on Friday when about 400 police evicted demonstrators who had been camping in the city square for nearly a week.

Police used capsicum spray, horses and dogs to vacate the city square, with some dragging people away.

Up to 100 protesters were arrested and police were accused of using excessive force.

"I thought Victoria Police handled it exceptionally well. Everybody has a right to protest and we will uphold that but there is a limit," Mr Baillieu said today.

"These individuals, these groups were given ample time and fair warning and I think Victoria Police handled it very well."

The protest was halted but activists will set up camp at the Treasury Garden parklands later this week.

A spokesman for the activists, Nick Carson, says he is hopeful Friday's chaotic scenes will not be repeated this week.

"If the city of Melbourne or Robert Doyle or Ted Baillieu want to move their constituents out of their own public parks, then we'd just encourage them to do that peacefully," he said.