Japan first imposed the sanctions in October last year after Pyongyang conducted its first ever test of a nuclear device.
'No concrete progress'
Nobutaka Machimura, Japan's chief cabinet secretary, said on Tuesday: "We decided they [sanctions] should be continued because there has been no concrete progress on the abduction issue and also taking into general consideration of the situation regarding North Korea's nuclear programme.
"We will continue to urge North Korea to take specific action to resolve those pending issues."
Japan's move came despite positive steps made by North Korea during last week's Korean summit in Pyongyang and six-party talks in Beijing.
North Korea agreed during the six-party talks to disable its main nuclear complex and declare its weapons programme by the end of the year, in line with an aid-for-disarmament pact reached in February with South Korea, Japan, the US, China and Russia.
At the Korean summit, the North pledged to work with the South towards establishing peace on the peninsula and Roh Moo-hyun, South Korea's president, left saying he was confident Pyongyang would disable its nuclear programme.
But the abduction of Japanese citizens in the 1970s and 1980s is a major sticking point between Japan and North Korea, with Tokyo refusing to provide aid under the disarmament accord unless the North returns its citizens.
In 2002, North Korea admitted to 13 abductions in the 1970s and 1980s and has since returned five kidnap victims along with their spouses and children.
|North Korea returned five Japanese abductees |
in 2002 and said the eight left were dead [EPA]
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 Kim Jong-il, the North Korean leader, had told Roh that there were no abductees in his country and the case with Japan had already been closed.
Masahiko Komura, Japan's foreign minister, said he was not aware of Kim's remarks.
"We believe there are survivors and we want North Korea to return them," he said.
Japan's $180m worth of trade with North Korea in 2005 was only about half that of 2002 and it dwindled to a trickle last year.
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 had been a key conduit of funds to the isolated state and had been suspected of being used to smuggle parts for Pyongyang's missile programme.
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 but did not set a date.
Yasuo Fukuda, the Japanese prime minister, has urged North Korea to take concrete steps to resolve the abduction issue, saying Tokyo was also willing to settle "the unfortunate past" resulting from Japan's 1910-1945 colonial rule of the Korean peninsula.