SEOUL – South Korea on Sunday proposed "final" talks with the North over the fate of a shuttered joint industrial zone, suggesting it may permanently close the estate if the negotiations fail.

The latest offer came after six recent rounds of talks aimed at reviving the Seoul-invested Kaesong complex in North Korea – suspended since April – produced little signs of progress.

"We are offering the final talks to discuss the issue (of Kaesong)," Ryoo Kihl-Jae, Seoul's unification minister in charge of cross-border affairs, told reporters.

Seoul will send a formal proposal across the border Monday, he said, without elaborating on when the talks would be held.

The Kaesong complex, built in 2004 as a rare symbol of cooperation, had survived previous inter-Korean crises but eventually became the most high-profile casualty of two months of elevated tensions following a nuclear test by the North in February which sparked international condemnation.

Production at the estate, 10 kilometres (six miles) 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.

Ryoo reiterated that the South wants the North to accept responsibility for what Seoul insists was the unilateral closure of Kaesong by Pyongyang, and give a written guarantee that it will never happen again.

"We want a clear answer from the North on preventing a recurrence," he said.

"Otherwise, we will be left with no choice but to make a grave decision to prevent even bigger damages on our companies in the future," he said.

The North has said it was not responsible for the shutdown, arguing that its hand was forced by hostile South Korean actions and intimidation – in particular, a series of joint military exercises with the United States.

Meanwhile, in an apparent gesture to lure Pyongyang to a fresh round of negotiations, Ryoo said Seoul would approve Monday five shipments of humanitarian aid for the North worth 1.4 billion won ($1.25 million).

But Lim Eul-Chul, a professor of North Korean Studies in the South's Kyungnam University, said the aid offer was unlikely to entice Pyongyang back to the negotiating table.

"The grants on private aids are not significant enough to make the North suddenly take responsibility for the shutdown and offer the guarantee against reoccurrence," he said, adding that Seoul was also not likely to budge on its key demands.

"Unless the North dramatically changes its course, I think that Kaesong will soon face a permanent closure," he said.

The latest sixth round of talks held on Thursday ended in a bitter mood, with no date set for another meeting and the North's officials accusing their Seoul counterparts of being "arrogant".

Pyongyang's chief delegate Pak Chol-Su also warned Thursday that the North's army may re-occupy Kaesong unless the two sides agree on reopening the zone – a valued source of hard currency for the impoverished state.

The North had relocated its military facilities in order to make room for the estate.