A former Muslim has taken to the multicultural streets of Lakemba in Sydney's west to ask local believers whether it is okay for people to criticise their religion.

Iranian-born author Armin Navabi visited Lakemba - considered Australia's unofficial Muslim capital - to act out the controversial social experiment.

Mr Navabi, an ex-Muslim now living in Canada, was told by one man that non-believers faced 'Islam or death' - while another Muslim said police should 'attack' those who mock their faith.

Others interviewed said they encouraged discussions about their Muslim faith, but stressed the importance of approaching the topic with the 'utmost respect'.

The author said he was prompted to visit Lakemba after far-right Canadian activist Lauren Southern clashed with police while trying to visit a mosque in the suburb.

Southern was told not to visit the mosque with her film crew for fears it would incite violence and be a 'breach of peace'.

In his viral video, Mr Navabi said some people felt they could not criticise Muslims because 'they are too sensitive and will react negatively'.

Many of the locals interviewed in the video took the stance that they were open to discussion and dialogue around their faith.

'We live in a democratic country. We criticise other people when they do the wrong thing. Why are we immune from that?' one person said.

The majority stressed it was important for any criticism or questions to be posed with the utmost respect.

Mr Navabi, an ex-Muslim now living in Canada, was told by one man he faced 'Islam or death' - while others said police should 'attack' those who mock their faith

'Everything is criticisable, with respect,' another man said.

'Especially because religion is a sensitive topic for everyone.'

After further questioning of one man, Mr Navabi was told he believes the Muslim community eventually wants Sharia Law to be established worldwide.

'100 per cent that is my goal – and every Muslim's goal. To establish Sharia law on earth,' the man claimed.

Mr Navabi questioned whether this meant 'somebody like me' who had turned his back on Islam would be 'killed' if Sharia law was in place.

'That's Sharia law, that's what I believe in,' the man stated.

'There's two choices, Islam or death.'

Many of the locals questioned in the video took the stance that they were open to discussion and dialogue around their faith: 'We live in a democratic country. We criticise other people when they do the wrong thing. Why are we immune from that?'

Another man said that anyone who criticised Islam should be attacked by police.

'If people criticise then it's bad yeah, and the police need to attack them,' the man said.

Mr Navabi also spoke with a local sheikh who said he was open to questions about Islam as he hoped it would help answer any misconceptions people have.

But when Mr Navabi asked if it was okay to 'mock' Islam, the sheikh's response took a turn.

'When somebody comes and mocks any religion and they say that my intention inside was a good thing, there's not one scenario in the entire globe where you mock somebody for the sake of goodness,' he said.

Another respondent said that anyone who criticised Islam should be attacked by police

He said that anyone who finds it normal to mock and laugh at other people have 'lost human morality' and 'lost all senses of being a human'.

When Mr Navabi then stated his own opinion that mocking somebody formed part of freedom of expression, the sheikh called it 'most disgusting'.

Mr Navabi commended him for meeting with him and being willing to have a conversation.

'There are still many people here willing to listen to you and have a conversation with you,' he said.

'These conversations are not pointless.'