The United States will consider meeting North Korean officials if they make good on nuclear disarmament pledges, but they first "must change their behaviour", a top US envoy said Monday.

"The basic, most important point that has to be underscored is that it's really up to North Korea to take the right steps," Glyn Davies, the US special representative on North Korea, told reporters after meeting Japanese officials.

"They need to change their behaviour. They need to cease their provocative actions. They need to fulfil their obligations to de-nuclearise," he added.

The nuclear-armed North, having alarmed South Korea, the United States and others with revelations about its uranium enrichment programme, wants six-party disarmament talks to resume.

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

Washington may "soon" review Pyongyang's calls to re-start the talks, which involve the United States, China, the two Koreas, Japan and Russia, Davies said. But he added: "We are not there. We still have some ground to cover."

The North quit the negotiations in April 2009, a month before staging its second atomic weapons test.

"We may have a chance in a coming period relatively soon to test their proposition that North Korea is ready to do the right thing... so that we can begin to contemplate an eventual return to six-party talks," said Davies, a former ambassador to the International Atomic Energy Agency who took up his current post in October.

The diplomat, who visited Seoul before Tokyo on an Asian tour that will next take him to Beijing, also met with families of Japanese nationals abducted by North Korea in the 1970s and 1980s, reportedly for training as communist spies.

US envoy on North Korea arrives in Japan
Tokyo (AFP) Dec 11, 2011 - 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.