"We believe they are willing to sometimes sacrifice their own people for the objective to control the whole world," Abu Hamza, president of the Islamic Information and Services Network, told the Melbourne Herald Sun.
Hamza, who leads 250 Muslims at a Coburg mosque, said Sheik Mohammed Omran was not alone in believing the U.S. Government was behind the 2001 attacks.
Omran, a fundamentalist leader in Brunswick, has been criticized by Prime Minister John Howard for not strongly denouncing terrorism.
Omran alleges the Bush administration orchestrated the attacks to give the U.S. licence to invade Islamic countries.
Islamic Friendship Association spokesman Keysar Trad denied most Muslims saw a U.S. conspiracy behind the 2001 attacks, but said some were deeply suspicious of involvement.