US Secretary of State Condoleezza Rice has scrapped her trip to Asia so she can monitor the condition of ailing Israeli Prime Minister Ariel Sharon.
Rice was to meet ministers from Australia, China, India, Japan and South Korea at the first Asia Pacific Partnership on Clean Development and Climate, and to visit Indonesia's president to discuss issues ranging from bird flu to security.
State Department spokesman Sean McCormack said on Friday that Rice would likely visit Australia in March; the Indonesian trip has yet to be rescheduled.
A separate US strategic dialogue planned with ministers from Japan and Australia must also be rescheduled, McCormack said, though new dates haven't been set.
US Energy Secretary Samuel Bodman will take Rice's place at the Australian climate meeting this month.
The six countries gathering in Sydney account for nearly half the world's population, energy use and economic output, and US officials hope the conference will spur more private investment in the region while also creating cleaner energy technologies and slowing global warming.
White House environmental adviser James Connaughton said on Friday that the US will make a financial contribution toward environmental efforts.
The US, he said, would suggest ways to share US technologies used to reduce pollution with the countries at the meeting.