Police remain on high alert as a small but vocal group of anti-Islam, nationalist and far right protesters face off with anti-racism groups outside the Parramatta mosque, in response to last week's shooting.

A large police contingent – including the Public Order and Riot Squad, mounted police, Highway Patrol and general duties officers – is on the ground, keeping a small group of anti-Islam protesters and anti-racism groups apart. Residents have been warned to expect delays and major disruption this evening.

Anti-Islam protesters. (Mark Burrows)

Tensions have been high in Parramatta since a police employee was gunned down by 15-year-old Farhad Jabar on Friday, with far right and nationalist groups calling for protests against Islam.

Nationalist group Party for Freedom has organised today’s “Bulldoze the Mosque” rally and claim they are protesting in response to the shooting. Police initially expected "300-400" people to turn up, but only a handful of protesters - many of them armed with placards have turned up so far.

Mounted police and the Riot Squad are maintaining a 100m exclusion zone between the group and a larger group of people who say they are protesting racist groups in Australia.

Mounted police on the streets of Parramatta. (9NEWS)

"You hate society," Party For Freedom leader Nick Folkes yelled at an opposing crowd gathered about 100 metres away.

One of the anti-Islam protesters earlier walked quickly through the anti-racist protest, waving his middle finger.

"We are here to take a strong stand against these kind of views," a man addressing the anti-racist crowd said.

"These people are Nazis and they should not be welcome on our streets."

The Riot Squad in Parramatta. (9NEWS)

Parramatta Local Area Command’s Superintendent Wayne Cox earlier called for calm.

“People have the right to express their views – peacefully,” he said.

“Try and bypass Parramatta on your way home, if you can, if you need to leave early to get home, do it,” he said.

“Plan ahead.”

He said police would try and keep protesters and mosque attendees separate to minimise risk.

“We have a range of resources at our disposal and they will be positioned tactically,” he said.

Prime Minister Malcolm Turnbull. (9NEWS)

“But there is no intelligence to suggest that there is going to be any violence.”

Earlier, police issued a statement that advised “anyone engaging in this type of unlawful behaviour can be charged and prosecuted”.

"As police, our message is that any act of violence, regardless of the motivation will not be tolerated, and will be treated as the serious offence that it is,” it read.

Other anti-Islam rallies have been planned for Canberra and Bendigo tomorrow.

Prime Minister Malcolm Turnbull also called for calm ahead of the protests.

He said that vilifying community groups is “contrary to our national interest”.

“If you are doing anything to vilify another group in the community, how are you doing anything but working in contrary to our national interest… working against our national interest?” he said.

“Australia is the most successfully harmonious multicultural country in the world,” he told reporters this afternoon..

“And that is because of a fundamental Australia value: mutual respect.

One of the anti-racism protesters. (9NEWS)

"Respect is a two-way street."

The Facebook page dedicated to the “Bulldoze the Mosque Rally” in Parramatta states that the group is also tired of “weak political leaders and their refusal to accept the truth that Islam is a terrorist ideology”.

The group's application to hold a rally was denied by police.

Marsden Street will be closed between 4pm and 7pm between George and Macquarie Streets, as a result of the police operation surrounding the protest activity.

For details about route changes or to plan your trip go to www.transportnsw.info or call 131 500.