An Australian Islamic community centre linked to five men arrested for planning an attack at an Anzac Day First World War centenary event said on Thursday 23 April that it was closing down.

The Al-Furqan Islamic Centre in Melbourne said it was closing immediately due to what it called harassment.

More than 200 police launched a series of raids in Melbourne on Saturday 18 April following a month-long sting operation aimed at disrupting the alleged plot.

Victoria state Premier Daniel Andrews said the men were "associates" of Abdul Numan Haider, an Islamic State sympathiser who was shot dead last year after he stabbed police officers, and who was known to have attended the Al-Furqan Islamic Centre.

Al-Furqan said in a statement on its website that it would shut its doors immediately, citing what it called harassment from the media, police and government.

"We believe that given the constant harassment, pressure and false accusations levelled against the centre ... this is the best course of action for the protection of the local community, its members, and the broader Muslim community that is often implicated in these insidious campaigns," it said.

The Australian newspaper reported that the most senior Australian recruiter for the Islamic State in Syria, Neil Prakash, was also a former member of Al-Furqan.

In a video recently posted online, Prakash urges followers of the Islamic State to attack targets in Australia.

Australia has sent hundreds of soldiers to Iraq to help train forces fighting the Islamic State, heightening concerns about reprisal attacks. Canberra raised the national terror threat level to "high" for the first time last September, when hundreds of police conducted raids after receiving information that Islamic State supporters planned to conduct a public beheading.

Australia believes at least 70 of its citizens are fighting with the Islamic State group in Syria and Iraq, backed by about 100 Australia-based "facilitators".