SEOUL - A SOUTH Korean delegation left for North Korea on Tuesday to prepare for talks amid growing concerns over the future of their last remaining reconciliation project.

The South's unification ministry said a four-member team travelled to the estate just north of the heavily fortified border to check preparations for talks on Thursday.

The ministry says the fate of a South Korean estate manager detained by the North since March 30 must be a priority in the negotiations.

The estate's future has become increasingly uncertain as inter-Korean relations have worsened and the North's nuclear standoff with the outside world has intensified.

At previous talks, the North demanded a wage rise for its 40,000 workers at the Kaesong estate to US$300 (S$436) a month from around US$75 currently.

It also demanded an increase in rent for the estate to US$500 million, compared with the current US$16 million for a 50-year contract.

The impoverished country received US$26 million last year in wage payments from Kaesong. Some analysts say it may be willing to forgo the cash because it fears the effects of exposing its workers to a South Korean lifestyle.

Cross-border relations have been hostile for the past year after the South's conservative government rolled back Seoul's previous 'sunshine' aid and engagement policy with Pyongyang.

The North has intermittently restricted access to Kaesong and expelled some South Korean staff. -- AFP