President Barack Obama has called off his trip to Malaysia to tackle the U.S. government shutdown, the office of Malaysia's PM Najib Razak has said, according to BBC News.

Secretary of State John Kerry will represent him next week instead, the office said.

The U.S. government has partially shut down after the two houses of Congress failed to agree a new budget.More than 700,000 federal employees face unpaid leave, and national parks, museums and many buildings are closed.

Obama earlier vowed not to allow Republicans to undermine his signature healthcare legislation as a condition to restart the U.S. government. "They demanded ransom," Obama said.

Najib's office said Obama had called the prime minister on Wednesday to inform him that Kerry would address an entrepreneurship conference in Kuala Lumpur on October 11 in his place.

Obama's visit would have been the first by a U.S. president to Malaysia since Lyndon B Johnson in 1966.

Obama had been scheduled to begin a four-nation Asian trip on Saturday to boost economic ties. It would also have taken in Indonesia, Brunei and the Philippines.

There has been no confirmation yet of what Obama intends to do with the rest of the itinerary. This is the third time in three years Obama has called off Asian trips.

In 2010, a vote on health care and the Gulf of Mexico oil spill forced separate cancellations.

The U.S. government ceased operations deemed non-essential at midnight on Tuesday, Oct 1, when the previous budget expired.

National parks and Washington's Smithsonian museums are closed, pension and veterans' benefit cheques will be delayed, and visa and passport applications will go unprocessed.

However, members of the military will be paid.