South Korea on Monday issued another appeal for North Korea to lift an access ban on the Kaesong joint industrial park, which has already forced a dozen South Korean firms to halt operations.
"We urge the North again to immediately lift the ban ... and to change its course to help resume normal operations in Kaesong," Unification Ministry spokesman Kim Hyung-Suk told reporters.
The last remaining symbol of inter-Korean cooperation, Kaesong has become a pawn in an increasingly dangerous game of brinkmanship among Pyongyang, Seoul and Washington.
The North has banned South Korean managers and personnel from crossing the border to enter the complex -- 10 kilometres (six miles) inside North Korea -- since Wednesday last week.
So far 13 the 123 South Korean firms operating there have been forced to halt production due to fuel and raw material shortages.
With no additional staff, fuel or other materials allowed into the estate, dozens of other firms are expected to shut down this week, said Ok Sung-Suk, a spokesman for the South Korean firms.
"Things couldn't be more miserable for us, being unable to visit our plants only five minutes away," Ok told reporters at the border crossing.
Food and fuel supplies are "nearly bottoming out", Ok said, adding that shipment delays were resulting in order cancellations by worried clients.
North Korea has not prevented anyone leaving Kaesong, and 40 South Koreans were set to cross back into the South Monday, leaving 514 still in the complex.
About 53,000 North Korean workers produce goods ranging from shoes to watches at factories in Kaesong, which was built in 2004 as a rare symbol of cross-border economic cooperation.
Neither side has allowed previous crises to significantly affect the complex, a crucial hard currency source for the impoverished North and seen as a bellwether for stability on the Korean peninsula.
Tensions have been running high after a recent series of apocalyptic threats from the North in response to fresh UN sanctions imposed after it staged a long-range rocket launch and a third nuclear test.