SYDNEY, Australia — The government has told Muslims who settle in Australia that they must denounce terrorism, learn English as quickly as possible, and forget the ancient hatreds and prejudices of their homelands.

Islamic leaders should condemn terrorism unequivocally and embrace tolerance and freedom of speech, ministers said, amid fears that Australia could be subject to an attack similar to the London bombings last year.

“Migrants who come to Australia are expected to speak English and endorse basic Australian values, and it’s going to be a problem for future generations if they don’t,” the treasury minister, Peter Costello, said.

He added: “We have had the attitude that when you come to Australia, whatever arguments you might have had in the old country, we start again with a common set of values and a common language.”

Islamic leaders in Australia warned of increasing radicalization and the danger of race riots last week after the prime minister, John Howard, criticized Muslims for what he deemed their failure to integrate into Australian society.

Mr. Howard infuriated many Muslims by calling for them to make more effort to learn English, accept Western values, and treat women with greater respect.