N Korea will never fully give up nuclear weapons: top defector

North Korea will never completely give up its nuclear weapons, a top defector said ahead of leader Kim Jong Un's landmark summit with US President Donald Trump next month.

The current whirlwind of diplomacy and negotiations will not end with "a sincere and complete disarmament" but with "a reduced North Korean nuclear threat", said Thae Yong-ho, who fled his post as the North's deputy ambassador to Britain in August 2016.

"In the end, North Korea will remain 'a nuclear power packaged as a non-nuclear state'," Thae told the South's Newsis news agency.

His remarks come ahead of an unprecedented summit between Kim and Trump in Singapore on June 12 where North Korea's nuclear and missile programmes are expected to dominate the agenda.

North and South Korea affirmed their commitment to the goal of denuclearisation of the peninsula at summit last month, and Pyongyang announced at the weekend it will destroy its only known nuclear test site next week.

But it has not made public what concessions it is offering.

Washington is seeking the "complete, verifiable and irreversible denuclearisation (CVID)" of the North and stresses that verification will be key.

Pyongyang has said it does not need nuclear weapons if the security of its regime is guaranteed.

But Thae, one of the highest ranking officials to have defected in recent years, said: "North Korea will argue that the process of nuclear disarmament will lead to the collapse of North Korea and oppose CVID."