A controversial Islamic centre in western Sydney has closed its doors after claims members and supporters have been harassed by police and counter-terrorism security agencies.

The Al Risalah Centre closed on Friday, the same day the Federal Government announced it was raising the national terror alert from medium to high.

The centre became notorious for giving a platform to hardliners sympathising with global jihad.

Centre director Wissam Haddad cited financial reasons as the primary cause for the closure.

He also said Muslims were being unfairly targeted by the Government's proposed anti-terror laws.

"Ninety per cent of people who come here have been visited by ASIO," Mr Haddad said.

"My family members have been hassled and the family members of people who are regulars have also been hassled."

Mr Haddad said ASIO had asked friends and members of the centre about him and the activities of the Al Risalah Centre.

"They ask things like: 'Where does the centre get funding from? What do we teach? Am I connected to anyone overseas? Who do we fund and where we receive our funding from?" Mr Haddad said.

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Mr Haddad supports the Islamic State (IS) cause and knows some of the Australian men who have travelled to the Middle East to join terrorist groups, including Mohamed Elomar and Khaled Sharrouf.

An image of the Shahada flag used by IS features on his Twitter account and he is also close friends with Hamdi Al Qudsi, the alleged ringleader of a criminal syndicate sending Australians to fight in Syria.

Australia's involvement in action against IS 'frowned upon'

Mr Haddad is a strident critic of the Federal Government's decision to send personnel to the Middle East.

"Obviously Australia's involvement is going to be frowned upon if anything else. I'm not happy whatsoever and I condemn Australia's involvement in Iraq," he said.

Space to play or pause, M to mute, left and right arrows to seek, up and down arrows for volume. Listen Duration: 5 minutes 37 seconds 5 m Wissam Haddad says the Al Risalah bookstore closed last week. Download 10.3 MB

"Anyone getting involved in killing any Muslims anywhere is going to be a potential enemy or is an enemy of Islam itself and every single Muslim."

Mr Haddad also speaks on behalf of the organisation Millatu Ibrahim, which is banned in Germany and was founded by an Austrian Al Qaeda supporter.

He insisted the group was misunderstood.

"Millatu Ibrahim is not an organisation, it's a platform propagating the deen (religion) of Allah and calling people to Islam," Mr Haddad said.

"Its platform is worldwide. It's not an organisation that is worldwide, that's what people are confusing."

For Mr Haddad, loyalty to faith comes before everything else.

"If I was allowed to live somewhere else, I would do so and it's something I'll be looking into," he said.

"We're talking to lawyers about it and we're talking to some people in Parliament to see how we go about it."