President Barack Obama has postponed a visit to Malaysia due to the US government shutdown, Prime Minister Najib Razak said on Wednesday.

Obama was set to visit Malaysia for an address scheduled for October 11 as part of a four-country swing through Southeast Asia including international summits in Indonesia and Brunei.

It is not immediately clear whether the budget crisis in Washington will affect the rest of the US president's long-planned trip to Asia.

State news agency Bernama and other media outlets quoted Najib as saying Obama's trip was now off.

He would send Secretary of State John Kerry to Malaysia in his place, reports said.

"Obama expressed his disappointment that he was unable to visit Malaysia as scheduled," Najib was quoted as saying by the Malaysian Insider news website.

"However, the Secretary of State John Kerry will come... as Obama's representative."

A spokeswoman in Najib's office confirmed the reports, saying Kerry would step in for Obama during his planned speech at an entrepreneurs summit in Kuala Lumpur on October 11, but declined further comment.

The US president was also due to attend back-to-back summits of the Asia-Pacific Economic Cooperation (APEC) bloc on the Indonesian island of Bali and an East Asia summit in Brunei next week.

The Philippine government refused to comment on whether a planned stop by Obama in Manila would be affected.

"As of yesterday, the trip was still proceeding and pushing through. But given the situation (in the United States) we would certainly understand if they had to cancel," Philippine government spokesman Ricky Carandang told AFP.

The White House has not yet announced any changes to Obama's travel plans.

White House spokesman Jay Carney on Tuesday said: "We have no changes to announce to the president's schedule."