President Barack Obama said on Tuesday his push to rebalance U.S. foreign policy to focus more on Asia was not "a passing fad" of his presidency and, in a clear reference to China, said bigger countries should not dictate to smaller ones.

"I've worked to rebalance our foreign policy to make sure America is a key player in the region," Obama said in a speech on the sidelines of a summit in Vientiane, Laos.

He also said that a failure to move ahead with the 12-nation Trans-Pacific Partnership trade pact would "call into question America's leadership".

"I think it is important for the entire region and it is important for the United States," he said.