Japanese Crown Prince Naruhito has made a call to remember Japan's wartime past and the horrors of World War Two - remarks that come as Prime Minister Shinzo Abe seeks to recast his country's wartime history.

In an unusual intervention in the discussion, Naruhito's mild-mannered broadside was being interpreted in some circles as a rebuke to Abe, a key figure in the right-wing drive to downplay the institutionalized system of wartime sex slavery.

"I myself did not experience the war ... but I think that it is important today, when memories of the war are fading, to look back humbly on the past and correctly pass on the tragic experiences and history Japan pursued from the generation which experienced the war to those without direct knowledge," Naruhito told a news conference ahead of his 55th birthday on Monday.