Kim Hyok Chol led working-level talks in run to Donald Trump and Kim Jong Un's meeting in Vietnam.

A North Korean nuclear envoy who steered talks before a failed summit with the United States in February is alive, a South Korean legislator said on Tuesday, contradicting a South Korean news report that he had been executed.

There has been a series of conflicting reports in recent weeks about the fate of North Korea's negotiators after a second summit between North Korean leader Kim Jong Un and U.S. President Donald Trump broke down in Vietnam in February.

Kim Hyok Chol, who led working-level talks in the run-up to that summit with his U.S. counterpart, Stephen Biegun, is alive, said Kim Min-ki, a lawmaker who was briefed by South Korea's intelligence agency.

The lawmaker did not elaborate on Kim Hyok Chol's situation.

South Korea's Chosun Ilbo newspaper said last month that Kim Hyok Chol had been executed in March, but CNN quickly refuted the report, saying he was alive and in state custody.

Chosun Ilbo also reported that another senior official who was instrumental in preparing the failed summit with the United States, Kim Yong Chol, had been sent to a labour and re-education camp.

But a few days, later Kim Yong Chol appeared in a state media photograph with leader Kim Jong Un.

Seasoned North Korean diplomats have taken over the talks since the Hanoi summit, with a long-time veteran with knowledge of arms control set to lead a new round of negotiations.