South Korea expects the long-stalled negotiations on North Korea's nuclear program to resume next month.

The country's chief negotiator Kim Sook told a news conference in Seoul on Friday, after a trip to China.

"If preparations and consultations among the countries go smoothly, I expect the six-party talks will resume next month. We consider it more likely that talks will be resuming at the beginning of June rather than late in the month."

The nuclear talks have been deadlocked due to disputes between the United States and North Korea over Pyongyang's promised declaration of its past nuclear activities.

The talks, involving China, Japan, the two Koreas, the United States, and Russia, were last held in October.

Hopes for fresh talks have increased recently after Washington softened its stance and agreed to accept a less thorough nuclear declaration from Pyongyang.