Police have vowed to crack down on "extremist criminals" in the wake of Saturday's violent protest in Sydney's CBD in which six officers were injured.

Six people have been charged after hundreds of Muslims descended on central Sydney to voice their anger over an anti-Islamic film published on the internet.

The protest in Sydney followed similar action in the Middle East and North Africa which has left at least nine people dead in the past few days.

New South Wales Police Commissioner Andrew Scipione says he was shocked by the violent scenes where offices were reportedly pelted with glass bottles and police cars damaged.

"Some of the behaviour, it has absolutely floored me. To see a young child with a placard thrust in his hand, calling for the beheading of a person is simply something I cannot comprehend," he said.

"It's not what we teach our children. I was particularly affronted by that scene."

He has praised the work of the police involved in the incident.

"No police officer should go to work and expect this to happen. To see those scenes, it shows how violent that exchange was," he said.

Police yesterday set up strike force McAlister to deal with the violent protesters and Commissioner Scipione says police will do everything they can to keep the city safe.

"You can be assured, we are waiting. We will deal with you. This is a no-nonsense engagement. If you want to act like you are extremist criminals, we will treat you like you are extremist criminals," he said.

"This is not Libya. This is not the country where you come to do what we saw yesterday."

Police are examining surveillance and media footage of the protest in a bid to identify those behind the violence and Commissioner Scipione has urged those responsible to turn themselves in to police.

"If you are one of those people that you know are in those photos, it's better in that you come forward and talk to us because we will certainly be coming to knock on your door," he said.

One of the six protesters charged over the violent protest was denied bail yesterday when he appeared via video link in the Parramatta Local Court.

Ahmed Elomar, 27, from Sydney's south-west, was charged with affray and breaching bail.

Police say Elomar was part of a group of protesters who were hurling bottle and other objects at riot officers.

Elomar is in custody and will appear in the Central Local Court tomorrow.

His co-accused are on bail to appear in court next month.

Sorry, this video has expired Six men charged over Sydney protest

Commissioner Scipione says some people among the crowd on Saturday were determined to make trouble.

"You don't wear a balaclava, you don't wear a face covering unless you are going to get up to badness and we saw plenty of those in the crowd," he said.

"Those involved in the violence - they didn't go there as protesters and they became extremist offenders."

Commissioner Scipione has thanked the wider Muslim community and Islamic leaders who have condemned the violence.

"To those leaders, to the general Islamic community, I want to thank you for your responsible handling of what has been a very bad incident," he said.

"No-one has benefited from this. I think this has been an afternoon that has cost a lot of people, certainly much in terms of the on going relations."

'Not the Australian way'

Prime Minister Julia Gillard says the behaviour was disgraceful.

"This kind of conduct has no place on the streets of our country. I also want to say very clearly, I do not want to see in the hands of anyone, particularly children, offensive signs that call for the killing of others. This is not the Australian way," she said.

Federal Opposition Leader Tony Abbott has also condemned the ugliness that took place on Sydney's streets.

"We expect every Australian to live in accordance with Australian values. Newcomers to this country are not expected to surrender their heritage, but they are expected to surrender their hatreds," he said.

Mr Abbott says he does not think the protest reflects the true nature of Australia's Islamic community.

"I do not believe the people on the streets of Sydney yesterday were truly representative of Islam," he said.

"I don't believe that the ugliness we saw on the streets of Sydney yesterday fairly reflects the Islamic people of our country."

Sorry, this video has expired Abbott condemns Sydney protests ( ABC News )

Mariam Veiszadeh, a lawyer and Muslim community advocate, told ABC News24 that many in the Muslim community are outraged by the behaviour.

"The individuals responsible for the violent outburst run completely contrary to Islamic tradition, and the rest of the community is equally as outraged and we sincerely hope this doesn't further damage relationships between the Australian Muslim community and the wider Australian community."

Meanwhile, police in the US questioned a Californian man with links to the film which was the catalyst for the protests.

Nakoula Basseley Nakoula, 55, a Coptic Christian, was interviewed for 30 minutes over possible violations of his probation for a bank fraud conviction.

Mr Nakoula has been widely linked to the low budget film, Innocence of Mulsims, which mocks the Prophet Mohammad and portrays him as a buffoon.