Japan extended sanctions against North Korea on Tuesday, saying it needed to keep pressure on the reclusive communist state to resolve a feud over Japanese nationals abducted decades ago.

The Japanese cabinet endorsed the extension for six months from Sunday of the sanctions, which ban North Korean imports and bar North Koreans ships from calling at Japanese ports.

The punitive measures were imposed after Pyongyang conducted its first nuclear test last October and were extended in April until mid-October.

Tokyo's decision to retain sanctions follows a disarmament pact sealed at six-part talks last to take North Korea a step closer to abandoning its nuclear arms ambitions.

"We saw the need to extend the sanctions because there has been no progress over the abduction issue," Chief Cabinet Secretary Nobutaka Machimura told reporters.

"We also took into comprehensive consideration the overall situation involving North Korea, including the nuclear issue."

The fate of the abductees is a highly emotive issue in Japan.

Pyongyang has admitted that its agents had kidnapped 13 Japanese in the 1970s and 1980s, five of whom have since been repatriated.

North Korea says the other eight are dead, but Tokyo wants more information about their fate as well as information on another four people it says were kidnapped.

Media reports said North Korea leader Kim Jong-il had told South Korea President Roh Moo-hyun last week that there were no abductees in his country and the case had already been closed.

Japanese Foreign Minister Masahiko Komura said he was not aware of Kim Jong-il's remarks.

"We believe there are survivors and we want North Korea to return them," he told reporters.

A source in Tokyo with close ties to North Korea said Tokyo's move could put a damper on bilateral efforts to improve ties.

Japan's trade with North Korea amounted to about $180 million in 2005, about half that of 2002, and dwindled to a trickle last year.

But a ban on the Mangyongbong-92 luxury ferry has blocked the only regular direct link between Japan, with its large Korean population, and North Korea.

The service has been a key conduit of funds to the isolated state, had been suspected of being used to smuggle parts for Phongyang's missile program.

Japan established diplomatic relations with capitalist South Korea in 1965, but it has yet to do so with the communist North.

Japan and North Korea last held talks in September on forging diplomatic ties, but failed to make any visible progress. They did agree to meet again, although no date has been set.

"We will continue to urge North Korea to take specific action to resolve those pending issues," Machimura said.