"It's not something that should wait until the nuclear problem is solved, as though somehow it's (the realignment) going to weaken our posture," Wolfowitz told a news conference at the end of a six-day tour to Singapore, Seoul and Tokyo.

"To the contrary, it's part of an effort to strengthen our overall posture...The issue of timing should relate to when our two countries have adequately consulted about the changes and come to a reasonable level of mutual agreement," he added.

Wolfowitz, the most senior Pentagon official to visit East Asia since President Bush took office, has tried to reassure South Korea and Japan that US force changes will enhance deterrence capability against communist North Korea.

The latest crisis on the Korean peninsula erupted last year after US officials said Pyongyang had admitted pursuing a secret nuclear arms program in violation of a 1994 agreement.

South Korea, home to 37,000 US troops, shares a heavily militarized border with the North.

Japan is in direct range of Pyongyang's missiles.

Both are keen to see a diplomatic solution but Washington has refused to rule out any option, including military action.

Wolfowitz said a speedy resolution to the North Korean crisis was impossible and that patience was essential.

Talks have been stalled since a meeting between US and North Korean officials in Beijing in April at which Washington says Pyongyang's negotiators said they possessed nuclear arms.

Wolfowitz's message has been that restructuring of 100,000 US military personnel in Asia -- part of a look at US forces worldwide -- is proceeding apace, with Washington aiming to reach agreement on adjustments in South Korea by the end of the year.