WASHINGTON - The Obama administration would be willing to hold bilateral talks with North Korea but only if certain conditions were met, the president's top adviser on Asia said on Friday.

President Barack Obama leaves on Wednesday on a trip to Japan, Singapore, China and South Korea, during which advisers had said North Korea's nuclear ambitions will be one of the important security issues discussed.

We are prepared to engage directly with the North Koreans, Jeffrey Bader, senior director for Asian Affairs at the National Security Council, said during a pre-trip briefing at the Brookings Institution think tank in Washington.

The Obama administration believes it is better to hear directly from others, including adversaries, than to hear from them secondhand through a filter. But we are not interested in talks for talks' sake, he said.

Washington and its allies have been trying to prod a reluctant North Korea back to the six-party talks -- involving China, the United States, North Korea, South Korea, Japan and Russia -- on ending its nuclear arms program.

Pyongyang quit the disarmament-for-aid talks in April and announced it would resume its nuclear development activities. The North held its second ever nuclear test in May, prompting fresh international sanctions.

Obama administration officials have insisted that any bilateral contacts with North Korea result in the rapid resumption of the stalled six-country negotiations.

We are ready to talk to North Korea in the context of the six-party talks with the explicit goal of denuclearization and with a recognition that its previous commitments to denuclearize and return to the nuclear non-proliferation treaty, notably those in 2005, remain valid, Bader said.

We are not interested in indulging North Korea's dream of validation as a self-proclaimed nuclear power, he said.

Chinese Premier Wen Jiabao last month courted North Korea's secretive top leader, Kim Jong-il, with a visit and Kim in turn signaled his state could return to the six-party talks.

Bader said Washington and Beijing have discussed North Korea more than any other issue and that the Obama administration is pleased with China's approach, although the two sides have differences.

There is no subject that has more preoccupied us than our relationship with North Korea, he said. If you did a pie chart on how much time has been spent on issues, North Korea would dominate.

Bader said he did not doubt that China is serious when it says it will not tolerate a nuclear North Korea.

We welcomed Premier Wen's visit and what he came back with and we're evaluating it, talking to our partners about, whether we can proceed in that respect, he said. By and large, I think we have a high level of satisfaction with the Chinese on what we are doing on North Korea.

(Editing by Sandra Maler)