A TUNNEL at an underground North Korea nuclear site has reportedly collapsed killing up to 200 people.

The disaster happened at the Punggye-ri nuclear test site in the north-east of the country on October 10, according to Japan's TV Asahi.

The disaster has prompted fears of a massive radioactive leak which could spark a Chernobyl- or Fukushima-style disaster.

A North Korean official said the collapse happened during the construction of an underground tunnel, South Korea's Yonhap news agency reports.

Some 100 people are said to have been trapped by the initial tunnel collapse, with a further 100 lost in a second collapse during a rescue operation, Asahi reported Tuesday.

Lee Eugene, a spokeswoman at South Korea's unification ministry, said: "We are aware of the report but do not know anything about it."