The top US envoy on North Korea Thursday urged the communist state to take concrete steps to revive long-stalled nuclear disarmament talks, saying he had no interest in "talks for talks' sake".

Glyn Davies, the US special representative on North Korea policy, said the North must honour a 2005 agreement, in which Pyongyang promised to give up nuclear programmes in return for economic and diplomatic gains.

"They need to indicate to us that they are prepared to take concrete steps to make it worthwhile to get back into the six party process," Davies told reporters during a visit to Seoul.

"I hope at some point, in the not too distant future, we will have an opportunity to get back to the table with them. But quite frankly we are not interested in talks for talks' sake," Davies said.

Davies, a former ambassador to the International Atomic Energy Agency, will also visit Japan and China on his first Asian tour since he took over the role in October.

The nuclear-armed North wants the six-party disarmament forum to resume without preconditions and says its uranium enrichment programme -- first disclosed to visiting US experts one year ago -- can be discussed at the talks.

The United States however says the North must first show "seriousness of purpose" toward denuclearisation by shutting down the programme.

The communist state quit the multi-party negotiations, which involve the United States, China, the two Koreas, Japan and Russia, in April 2009, a month before staging its second atomic weapons test.

Nuclear envoys from Washington and Pyongyang met in New York in July and in Geneva in October to discuss ways to revive the six-party negotiations but reported no breakthrough.

The North said earlier this month it is making rapid progress in enriching uranium and building a new reactor.

It says the enrichment is aimed at producing electricity but critics fear the project could give the North a second way to make weapons in addition to its existing plutonium-based bombs.