Australia will launch airstrikes against Islamic State (ISIS) targets in Syria within days and resettle an additional 12,000 refugees from the deepening humanitarian and security crisis in the Middle East, Prime Minister Tony Abbott said Wednesday.

He also announced that his government will pay an additional 44 million Australian dollars ($31 million) to keep 240,000 Syrians and Iraqis in refugee camps in Jordan, Lebanon and Turkey, bringing the Australian contribution to the humanitarian crisis in Iraq and Syria to AU$230 million since 2011.

Australia's six F/A-18 Super Hornet jet fighters based in Dubai have been bombing targets in Iraq since October last year. Australia is moving across the border, where the legality of airstrikes is less clear, at the request of the United States.

"There can be no stability and no end to the persecution and suffering in the Middle East until the Daesh (Islamic State) death cult is degraded and ultimately destroyed," Abbott told reporters. "This is very much in Australia's national interest."

The 12,000 refugee places announced on Wednesday are in addition to Australia's usual annual refugee intake of 13,750.

Air Chief Marshal Mark Binskin, Australia's Defense Force Chief, said the first Australian airstrikes against Syrian targets would be launched this week.

"Combat operations are dangerous by the nature of what the men and women are doing," Binskin said. "I don't envisage a marked increase in the risks of operating where we're going to operate in Syria."

The government can commit to the Syrian campaign without asking Parliament. While the opposition Labor Party supported Australian military involvement in Iraq at the request of the Iraqi government, it questioned the legality and purpose of extending the campaign into Syria,

"What's the objective here? What's the end game? It's not enough to be speaking in sound bites about what an evil organization Daesh is," opposition deputy leader Tanya Plibersek said.

Richard Di Natale, leader of the minor Greens party, said: "The decision ... to drop bombs on the Syrian people is going to make a bad situation much worse."

United States, Canada and Middle Eastern allies Bahrain, Saudi Arabia, Jordan and the United Arab Emirates have been striking targets in Syria for months. Britain is also considering bombing missions over Syria, while British pilots embedded with other militaries have already done so.