Australian Prime Minister Tony Abbott on Wednesday said moves were underway to ban "race hate" preachers from entering the country to prevent them peddling "alien and extremist" ideologies.

Australian fighter jets have flown their first armed combat mission in Iraq against the Islamic State group but did not launch air strikes, the military said Monday.

The White House on Friday praised Australia over its decision to join air strikes in Iraq and to send special forces military trainers to the country.

"With these deployments, Australia demonstrates its continued leadership and resolve in addressing the urgent and critical security challenges that threaten Australia, its people, and the broader international community," White House spokesman Josh Earnest told reporters on Air Force One.

Australia has ordered an inquiry into claims of sexual misconduct by staff at a refugee camp in Nauru, including whether the reports were fabricated by aid workers, Immigration Minister Scott Morrison said Friday.

Australia's cabinet Friday authorised military air strikes on the Islamic State group in Iraq and the deployment of special forces troops to combat the militants, Prime Minister Tony Abbott said.

Australian Prime Minister Tony Abbott said Wednesday his country's military jets were set to join the United States in its war against Islamic State jihadists through support flights over Iraq.

Australia deployed some 600 troops and several aircraft to the United Arab Emirates in mid-September as it geared up to join the U.S.-led international coalition.

A man was arrested in counterterror raids in Australia on Tuesday, with police alleging he was sending money to a U.S. jihadist fighting with a militant group in Syria.

The arrest comes days after a terror suspect was shot dead in Melbourne after stabbing two police officers, and amid concerns about Australians fighting alongside jihadists in Iraq and Syria.

The search for Malaysia Airlines Flight MH370 enters a new underwater phase this week almost seven months after the jet went missing, with two specialist ships to join the hunt.

MH370 disappeared en route from Kuala Lumpur to Beijing on March 8 with 239 people onboard and no trace of the Boeing 777-200 has been found despite a massive air, sea and underwater search.

Remnants of volcanoes, towering ridges and deep trenches have been discovered on the seabed of the southern Indian Ocean by experts mapping the underwater terrain as part of the search for missing Malaysian Airlines flight MH370.

Australian authorities released the three-dimensional images on Friday, revealing for the first time details about the seafloor where efforts are being concentrated to find the jet, which is presumed to have crashed into the sea on March 8.

Australian Prime Minister Tony Abbott said Friday he was deeply worried about the potential for lone wolf terror attacks, days after an 18-year-old suspected militant was shot dead while attacking police.

Abdul Numan Haider was killed on Tuesday after he stabbed two police officers outside a Melbourne police station, seriously injuring one he knifed in the head, neck and stomach.