TOKYO (REUTERS) - Japan decided on Thursday to ease some sanctions on North Korea in return for its reopening of a probe into the fate of Japanese citizens abducted by the reclusive state decades ago, as a fresh report emerged that some of them were alive.

"This is just a start," Prime Minister Shinzo Abe, who has made the fate of the abductees a focus of his political career, told reporters. "We will make every effort to achieve a complete resolution of this issue."

Japan will lift travel curbs to and from North Korea, restrictions on the amount of money that can be sent or brought to the impoverished North without notifying Japanese authorities, and allow port calls by North Korean ships for humanitarian purposes.

Easing the sanctions will likely have only a minimal economic impact, but it could be a first step towards repairing long-chilled ties between Tokyo and Pyongyang.

The decision comes at a time of persistent international concern about the volatile North's nuclear and missile programmes.

Abe said the government had determined that North Korea took an unprecedented step in establishing a new entity to investigate all Japanese nationals involved.

The Nikkei business daily said on Thursday that North Korea had handed Japan the names of at least 10 of its nationals said to be living in that country, including some of those believed to have been abducted. Japan's Chief Cabinet Secretary Yoshihide Suga however said the government had not received any report of such a list.

Tokyo will analyse the list to see if any names match those of reported abductees, and Pyongyang is expected use the list to confirm their whereabouts, the daily said.

Japan has stressed that its decision will not mean it is out of step with its allies, the United States and South Korea, on dealing with North Korea, but some analysts said cracks were beginning to show.

"It seems to me that it's going to become harder and harder for the US to pretend that everything is fine in terms of coordination on DPRK (North Korea) policy as Japan moves down this road," Joel Wit, a former US State Department official and visiting fellow at the US-Korea Institute at Johns Hopkins School of Advanced International Studies in Washington, told Reuters in an e-mail.

North Korea agreed in May to reopen the probe into the status of Japanese abductees, who were taken in the 1970s and 1980s to help train spies. In return, Japan promised to lift some of its sanctions when the investigation was launched.

Pyongyang, however, has a history of reneging on deals. It admitted in 2002 to kidnapping 13 Japanese citizens, and five abductees and their families subsequently returned to Japan.

North Korea said the remaining eight were dead and that the issue was closed, but Japan pressed for more information about their fate and others that Tokyo believes were also kidnapped.

In 2008, Pyongyang promised to reopen the probe of Japanese abduction victims but it never followed through. It also reneged on promises made in multilateral talks aimed at ending its nuclear weapons programme and declared the negotiations had ended.

Japanese diplomats met their North Korean counterparts in Beijing on Tuesday to assess Pyongyang's latest plan.

Some critics have said that North Korea already knows the fate of the missing Japanese and that the promised reinvestigation was largely a diplomatic ploy.

The list of Japanese nationals in North Korea, which is in the Korean language, includes names and personal histories, according to Japanese government officials involved in the talks, the Nikkei said.

The Japanese sanctions that could be lifted are separate from those imposed by Japan and other UN members under UN sanctions that followed Pyongyang's first nuclear test in 2006. The North is banned from conducting atomic and missile tests, and UN member states are barred from weapons trade with Pyongyang and from financial transactions that facilitate them.

"Basically, Japan's planned steps are little more than nominal ... They are not substantive. They are not something that would benefit North Korea greatly," said Hajime Izumi, a professor at the University of Shizuoka. "There is no telling whether they can make substantial progress from here."

Proof that some of the missing Japanese are alive would almost certainly boost Abe's popularity following signs of slippage due to his government's announcement on Tuesday of a historic shift in security policy by ending a ban that has kept the military from fighting overseas since World War II.

Abe's support slipped 4.3 points to 47.8 per cent in a Kyodo news agency survey released on Wednesday, while his disapproval rating stood at 40.6 per cent - the highest since he returned to office in December 2012 promising to revive the economy and bolster Japan's security stance.

"The 'revelation' that there are more than 10 survivors is encouraging but the timing seems to divert attention away from Abe's extremely unpopular coup against Japan's postwar pacifist order," said Jeffrey Kingston, director of Asia studies at Temple University's Japan campus.