Senior diplomats from the US and South Korea have arrived in Beijing for talks aimed at trying to restart stalled negotiations on ending North Korea's nuclear weapons programme.

The visits come amid an escalation of of diplomatic activity aimed at persuading the North to return to multilateral talks.

Stephen Bosworth, the US envoy to North Korea, is expected to hold talks on the issue with China's Vice Foreign Minister, Wu Dawei, in Beijing on Wednesday, Chinese and US officials said.

South Korea's chief negotiator, Wi Sung-Lac, held talks with Wu on Tuesday.

The discussions in the Chinese capital come after a senior North Korean official held talks with Hu Jintao, the Chinese president, on Tuesday.

According to the state-run China Daily newspaper Kim Yong-Il, the North Korean premier, delivered a message from North Korea's leader, Kim Jong-Il, although the paper did not say what the message contained.

The six-party disarmament talks have been on hold since the North stormed out last year before going on to conduct a second nuclear test.

That test and a subsequent launch of a long-range rocket prompted a tightening of UN sanctions.

North Korea wants those sanctions to be lifted before it returns to the negotiating table.

The talks bring together envoys from China, the US, Russia, Japan and the two Koreas.

China, which has hosted the negotiations and is North Korea's only major ally, has said the future of the talks depends on the willingness of Washington and Pyongyang to work together.