Pyongyang's chief nuclear envoy is likely to visit the United States early this month to discuss the resumption of the stalled nuclear disarmament talks, Seoul's top diplomat said on Wednesday.

Chinese experts tracking the Korean Peninsula nuclear issue said positive signals regarding the rare visit, if it takes place, was an indication that Pyongyang was softening its stance, and that the stalled Six-Party Talks could see a breakthrough soon.

The foreign minister of the Republic of Korea (ROK) Yu Myung-hwan told reporters in Seoul that the top nuclear negotiator of the Democratic People's Republic of Korea (DPRK) Kim Kye-gwan has been invited to attend an academic meet in the US.

US officials, however, are reluctant to sit down for direct talks unless there is a clear indication that such a dialogue would quickly lead to a resumption of wider nuclear disarmament discussions, he said.

The DPRK, on the other hand, said at the UN-backed Conference on Disarmament held in Geneva on Tuesday that it would like to directly talk with the US on the nuclear issue, but that Washington must drop its "hostile policies".

"This is a signal of Pyongyang's softened stance on the nuclear disarmament talks," said Fu Mengzi, a senior researcher on American studies at the China Institutes of Contemporary International Relations

"Washington has been sticking to a tough line on conditions to restart the talks, and now Pyongyang is seeking to ease the tension," Fu said.

Pyongyang has insisted on two conditions for returning to the talks frozen since April last year - lifting UN sanctions and holding peace talks aimed at formally ending the 1950-53 Korean War.

At the same time, it has suffered heavily from UN sanctions and a failed currency reform.

The US, ROK and Japan however have said Pyongyang must first return to the talks and show notable progress before its conditions can be met.

Liu Jiangyong, a renowned scholar on East Asian studies, said Washington's approach, of avoiding direct talks with the DPRK envoy unless there was "wider talks on the nuclear issue", has pressured Pyongyang to indicate that it was willing to return to the negotiating table.

"They are testing each other's willingness after recent negotiations among the countries involved," he said.

In February alone, three high-profile meetings have been held between senior officials from Beijing and Pyongyang. This week, two senior US envoys on the DPRK issue wrapped up a tour to the region for talks with China, the ROK and Japan, while the top ROK nuclear envoy has also just returned from a trip to Beijing.

As for the "hostile policies", the DPRK is referring to the establishment of a peace mechanism mentioned in past Six-Party Talks agreements and lifting of sanctions, Liu said.

Seoul seems to be uncomfortable with the possible direct talks between Washington and Pyongyang that leaves other sides out.

"Countries concerned do not welcome DPRK's attempts to discuss its nuclear issues only with the US," ROK Foreign Minister Yu Myung-hwan said at Wednesday's press briefing.

"But since the DPRK nonetheless is hoping for bilateral discussions with the US for whatever political reasons, such talks, if held, would be taking place within the Six-Party framework," he said.

An unnamed high-level ROK official said earlier this week that the Six-Party Talks, which also involves Russia, would resume as early as in "March or April", following similar expectations raised days earlier by the US.