Australian Prime Minister John Howard is beginning a 10-day trip to the US and Britain that will be dominated by the US-led war on terror.
Mr Howard will visit Australians injured in the London bombs
The veteran Conservative leader has been a staunch supporter of the campaigns in Iraq and Afghanistan.
Australia has 1,400 troops in the Iraq area. On Wednesday it announced it was sending more troops to Afghanistan.
However domestic critics say such support has made Australia more likely to be targeted by militants.
The BBC's Phil Mercer in Sydney says Mr Howard is guaranteed a very warm welcome in Washington and London.
Mr Howard's trip to Washington will give him his first opportunity to meet President George W Bush since both men triumphed in elections last year.
The Australian leader will spend time with senior members of Mr Bush's cabinet, including Vice-President Dick Cheney and Secretary of State Condoleezza Rice.
Mr Howard dismissed suggestions that his support for US policies in Iraq could make Australia a target for terror attacks.
"If you imagine you can buy immunity from fanatics by curling yourself in a ball and apologising to the world for who you are, not only is that morally bankrupt, it's also ineffective," he said.
Mr Howard added that the fact that those responsible for the London bomb blasts were UK citizens underlined the problem governments had in fighting terrorism.
"We shouldn't complacently imagine that there aren't potentially suicide bombers in this country," he said.
Mr Howard will spend six days in Washington, before going to London.
He will hold talks with his counterpart Tony Blair, and Queen Elizabeth II.
He is also expected to visit Australians injured in the London bombings.