North Korea's vice foreign minister Kim Kye-Gwan expressed hope that ties with Washington would improve as he arrived in New York for rare talks with US officials, Yonhap news agency reported.

"I believe North Korea-US relations will improve as now is the time for all countries to reconcile," Kim told reporters as he arrived Tuesday, the South Korean agency reported from the US city.

He added that he was "optimistic of the prospects for the six-way talks and the North-US relationship".

Pyongyang made a fresh call -- apparently timed for his arrival -- for a peace treaty with the United States, calling it essential for progress in stalled six-party talks on the North's nuclear disarmament.

Kim said he planned to meet Stephen Bosworth, the top US envoy on North Korea, on Thursday but gave no other details of his trip.

The veteran former nuclear negotiator is on his first visit to the United States since March 2007.

US Secretary of State Hillary Clinton announced the visit Sunday, two days after the nuclear envoys of South and North Korea held a surprise meeting on the sidelines of an Asian security conference in Bali.

The talks began in 2003 and were last held in December 2008.

North Korea in April 2009 announced it was quitting the forum in anger at UN condemnation of its long-range missile launch that month. It staged a second nuclear test in May 2009.

Efforts to restart the talks, which also include China, the United States, Japan and Russia, have been hindered by two deadly incidents last year on the inter-Korean border that Seoul has blamed on its neighbour.

The North's disclosure last November of a uranium enrichment plant, which could give it another way to make atomic weapons, are another complicating factor.

Clinton said Sunday the two sides would have an "exploratory meeting" to see if North Korea was prepared to live up its obligations under international and six-party talks commitments, and take concrete steps towards denuclearisation.

The North's official news agency, in a commentary Wednesday, said a peace agreement with the United States formally ending the 1950-53 war "may be the first step for settling the Korean issue including the denuclearisation".

The war, in which a US-led United Nations force defended the South, ended 58 years ago on Wednesday with an armistice. The two Koreas have remained technically at war because there has never been a peace treaty.

"It is impossible to wipe out the mutual distrust, nor is it possible to achieve a smooth solution of the issue of denuclearisation, as long as there persists the hostile relationship" between North Korea and the United States, the news agency said.