TOKYO - Japan's prime minister says he will meet North Korean leader Kim Jong Un face-to-face and restore diplomatic relations between the two long-time foes.

In a major policy speech to mark the opening of parliament on Monday, Shinzo Abe also vowed to push Japan-China ties "to a new stage" and pledged a record budget to improve crumbling infrastructure in the world's third-biggest economy.

Abe has long sought to resolve an emotional dispute related to North Korean agents' abduction of Japanese nationals during the Cold War era to train Pyongyang's spies.

"I will act resolutely, never failing to seize every opportunity to break the shell of mutual distrust, and I myself will directly face Chairman Kim Jong Un ... to resolve North Korea's nuclear and missile issues, as well as the abductions issue," he said.

Abe gave no timeframe for a potential meeting with the North Korean leader but the comments came as Kim ordered preparation for a second summit with US President Donald Trump, likely towards the end of next month.

"I will aim at diplomatic normalisation by settling the unfortunate past," Abe said, using a Japanese diplomatic euphemism referring to harm caused by Japan during its brutal colonisation of the Korean Peninsula before and during World War II.

The conciliatory message contrasted sharply from a year ago when Abe used the same parliamentary address to set out a hardline approach, pledging to "compel North Korea to change its policies" and describing Pyongyang's nuclear and missile programmes as an "unprecedentedly grave and urgent threat".

North Korean authorities have given no public indication of any willingness to meet Abe, while Pyongyang's state media regularly excoriate Japan over its past and Abe for ramping up defence spending.

A commentary by North Korea's official KCNA news agency earlier this month called Japan a "heinous criminal state against humanity", and an "immoral and impudent country".

Abe also omitted references to South Korea, which he had routinely mentioned as Japan's most important neighbour.

The two countries are currently locked in disputes over military issues and wartime history. Japan's defence ministry is reportedly considering not participating in a multi-national defence exercise planned in South Korea this spring.(FA)