"We believe they are willing to sometimes sacrifice their own people for the objective to control the whole world," said Abu Hamza, president of the Islamic Information and Services Network.

Mr Hamza, who leads 250 Muslims at a Coburg mosque, said Sheik Mohammed Omran was not alone in believing the US Government was behind the 2001 attacks on New York and Washington that killed almost 3000 people.

Sheik Omran, a fundamentalist leader at the Ahlus Sunnah wal Jam'ah Association in Brunswick, has been criticised by Prime Minister John Howard for not strongly denouncing terrorism.

Sheik Omran, while saying terrorism was evil, has said the Bush Administration orchestrated the September 11 attacks to give the US licence to invade Islamic countries.

Sheik Omran also believes there is no proof al-Qaida leader Osama bin Laden has anything to do with terrorism.

Mr Hamza agreed with the conspiracy theory, saying most Australian Muslims also believed the US was to blame.

"There are many Muslims, and I am one of those Muslims, that believe whatever Omran has said is correct.

"The majority of Muslims believe; they believe that even if Muslims have done it they have been given access to do this."

He said the US now had "a licence to go into Islamic countries . . . next it will be Syria, Saudi (Arabia)".

Mr Hamza said he and other Muslims condemned terrorist attacks, even if they were carried out by Muslims.

"(But) I can't believe that Muslims can do this."

He said the Koran forbade the killing of innocent people.

"John Howard said last week the Muslim leaders are not doing enough . . . what we fear is that this could create an atrocity between Muslims and non-Muslims."

Mr Hamza said creating a view that all Muslims supported terror was akin to saying that because one Christian priest was a pedophile then all priests were pedophiles.

Islamic Friendship Association spokesman Keysar Trad denied most Muslims saw a US conspiracy behind the 2001 attacks, but said some were deeply suspicious of involvement.

"Many don't care about the conspiracy theory," Mr Trad said.

"The rest of them say whoever was behind it, if it was bin Laden, he must have been able to buy the support of some traitors within America.

"It could be anyone, it could be the CIA. There is this theory he (bin Laden) has always been working for the Americans and this was just another mission.

"Others say bin Laden has nothing to do with it.