North Korea yesterday restored its hotline with South Korea and announced it would let businessmen from the South visit a shuttered joint industrial zone, Seoul officials said. The move came hours after dozens of South Korean firms threatened to withdraw from the zone at Kaesong in the North, complaining they had fallen victim to political bickering between the two rivals. "The hotline was restored this afternoon after North Korea accepted our request to normalise it," a South Korean unification ministry official said. The Kaesong estate, where North Koreans work in Seoul-owned factories, was the most high-profile casualty of the months of elevated tensions that followed the North's nuclear test in February. Operations at the complex ground to a halt soon after the North banned entry by the South's factory managers and other officials on April 3. In an unexpected change of course yesterday, the North sent a message to the South saying South Korean businessmen and managers would be allowed to visit the complex. It said the businessmen could take steps to avert damage to facilities during the rainy season. Representatives of the South Korean companies have repeatedly urged the two sides to open talks to revive the complex. "The manufacturers of machinery and electronics parts cannot wait any longer. Kaesong must be reopened ... or they have to move elsewhere", businessman Kim Hak-kwon said.