North Korea on Friday rejected a new request by businessmen from the South to deliver food and supplies to their staff inside a closed joint-industrial zone, officials said.

North Korea has blocked access to the zone in Kaesong -- which lies 10 kilometres (six miles) inside its border -- since April 3 amid soaring military tensions on the Korean peninsula.

South Koreans in the industrial zone were told they could leave when they wanted, but as of Friday there were still about 190 remaining.

The North barred a delegation of 10 businessmen representing the 123 South Korean firms in Kaesong from bringing food and other daily necessities to their staff on Wednesday, and turned down the group's request again Friday.

"In a notice sent today, North Korea said it would not allow them to visit Kaesong on April 22," a unification ministry spokesman told AFP.

The North withdrew all its 53,000 workers, suspended operations in the zone on April 8 and rejected Seoul's offers of dialogue to resolve the situation.

Kaesong was established in 2004 as a rare symbol of inter-Korean cooperation.

Neither of the Koreas has allowed previous crises to significantly affect the complex, which is seen as a bellwether of stability on the Korean peninsula.