SEOUL (AFP) - North Korea warned on Thursday that talks with South Korea on reopening their joint industrial zone were facing the prospect of collapse.

"Talks are in danger of breakdown," Mr Pak Chol Su, the North's chief delegate to the talks on the estate told reporters, according to pool reports.

He warned that the North may turn the estate into a military base if the talks collapsed.

"If the fate of Kaesong industrial zone ends like this, the military would reclaim it," he said.

North Korea had relocated its military facilities in order to make room for the zone, which opened in 2004 as part of former South Korean president Kim Dae Jung's Sunshine policy of reconciliation.

The North's warning came at the end of a sixth round of talks on the Kaesong estate. There was no word yet from the South Korean delegation.

Officials from both sides have already met five times this month but failed to narrow their differences on rescuing the zone in the North, suspended since April.

Some analysts said Thursday's talks would likely be the last chance to salvage Kaesong as tensions are likely to heighten again next month, when the South is set to hold an annual military exercise with the United States.

Production at the Kaesong estate, 10 kilometres over the border, has been suspended since North Korea withdrew its 53,000 workers from the zone in April at the height of soaring military tensions with the South.