The top US envoy on North Korea arrived in Tokyo on Sunday on the latest leg of his first Asian tour in the wake of Pyongyang's boast of progress in uranium production.

Glyn Davies, the US special representative on North Korea, plans to meet Japanese diplomatic officials and families of Japanese nationals abducted to North Korea in the 1970s and 1980s, public broadcaster NHK said.

Davies, who took over the role in October, said earlier in Seoul that the North must honour a 2005 agreement in which Pyongyang promised to give up nuclear programmes in return for economic and diplomatic gains.

"We are going to test the proposition that North Korea is prepared to move forward in that fashion," Davies told NHK as he arrived at Tokyo's Haneda airport. "If they do, then many things are possible."

Davies, a former ambassador to the International Atomic Energy Agency, visited Seoul before Tokyo, on his Asian tour which will also take him to Beijing.

The nuclear-armed North wants a 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.

But Davies said in Seoul that Washington was "not interested in talks for talks' sake."

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 negotiations but reported no breakthrough.

The North said late last month that 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.

Japan has taken a tough stand against North Korea, arguing Pyongyang kidnapped Japanese nationals to train spies and that some are still kept under wraps because they know secrets about the reclusive regime.