Kim Sook, named this week to head South Korea's team to six-nation talks, said stalled negotiations would resume as soon as North Korea fully declares its nuclear programmes.

"Talks on North Korea's nuclear issue are reaching a critical stage," Kim told a briefing. "We are pushing to resume the six-party talks as soon as the declaration is submitted. All participatory countries agree to this idea."

Kim, asked about a news report that said US diplomats plan to visit Pyongyang to get the talks moving, said: "It will be for the United States and North Korea to hold working-level discussions aimed at working out a declaration, which will be a main topic for the next round of six-party talks."

The United States, the two Koreas, China, Japan and Russia reached a deal last year which would grant North Korea energy aid and major diplomatic and security benefits in return for full denuclearisation.

But the talks have been stalled for months by a dispute over the communist state's nuclear declaration, which was promised by the end of last year.

Washington says the document should clear up suspicions about an alleged secret uranium enrichment programme and suspected proliferation to Syria. North Korea denies both charges.

Hopes of breaking the impasse emerged since last week when top US nuclear envoy Christopher Hill and his North Korean counterpart Kim Kye-Gwan met in Singapore to debate the form of the declaration.

US President George W. Bush has accepted the tentative deal reached in Singapore, according to White House spokeswoman Dana Perino on Monday.

"At the next round of talks, the evaluating and the verifying of the declaration will be given the top priority in consultations," Kim said.

"Negotiations for nuclear dismantlement will be a very difficult process, likely to be a very long road full of ups and downs," he added.