Nusa Dua: The United States said on Sunday it has invited a top North Korean envoy to New York for "exploratory talks" on the possible resumption of the six-party negotiations on denuclearisation.

Secretary of State Hillary Clinton said the North's vice foreign minister and former nuclear negotiator, Kim Kye-Gwan, would visit the US at the "end of next week".

The invitation was announced after envoys from North and South Korea held unexpected talks in Indonesia on Friday, on the sidelines of an Asian security forum which Clinton attended alongside ministers from China and South Korea.

"Following the first round of denuclearisation talks between the nuclear negotiators of the Republic of Korea and North Korea, the United States has invited North Korean Vice Foreign Minister Kim Kae-gwan to New York toward the end of next week," Clinton said in a statement.

In a statement released to reporters as she left Indonesia after three days of intense engagement with East Asian foreign ministers, Clinton said Kim would meet with an interagency team of US officials.

Their discussions would focus on the "next steps necessary to resume denuclearisation negotiations through the six-party talks", she said.

"This will be an exploratory meeting to determine if North Korea is prepared to affirm its obligations under international and six-party talk commitments, as well as take concrete and irreversible steps toward denuclearisation," Clinton said.

She said the United States had repeatedly affirmed its readiness to open talks with North Korea, but it was not prepared to offer any new concessions in order to re-start the stalled multilateral negotiations.

"We do not intend to reward the North just for returning to the table," Clinton said.

"We will not give them anything new for actions they have already agreed to take. And we have no appetite for pursuing protracted negotiations that will only lead us right back to where we have already been."

South Korea's  news agency, citing diplomatic sources in Seoul, earlier on Sunday reported that Kim would visit New York around Thursday.

Kim will discuss the North's nuclear issues and possible resumption of US food aid with Stephen Bosworth, the US special envoy on North Korea, as well as other officials, it said.