WASHINGTON (AFP) - An influential Japanese opposition lawmaker called on Wednesday on Prime Minister Shinzo Abe to work for more stable relations with the United States (US) and South Korea after rifts over historical disputes.

Mr Seiji Maehara, a former foreign minister and prominent member of the largest opposition Democratic Party of Japan, said that close allies Washington and Tokyo would inevitably have disagreements but should address them privately.

"Behind the scenes, we may fiercely argue with each other. But still we should showcase our strong bond to outsiders," Mr Maehara said in Washington at the Center for American Progress, a left-leaning think tank.

"We have to understand precisely which country would benefit from a worsening of the Japan-US relationship," Mr Maehara said, in a veiled reference to a rising China.

Mr Abe, a conservative who led his bloc to crush the Democrats in the last two national elections, on Dec 26 paid a pilgrimage to the Yasukuni shrine which honours 2.5 million Japanese war dead, and which China and South Korea associate with Japan's past militarism.

The US, in a rare rebuke of Tokyo, said it was "disappointed" by Mr Abe's visit. An aide to Mr Abe later hit back that it was Japan that was disappointed by the US, in a video that was taken down by the government which distanced itself.

Mr Maehara did not directly criticise Mr Abe, who is known for his right-leaning views on history, but noted that government leaders during the Democrats' 2009-2012 tenure refrained from visiting the Yasukuni shrine or reviewing Japan's historical apologies.

Mr Abe's government has said that it is reviewing but will not revise Japan's landmark 1993 apology to wartime sex slaves known as "comfort women", an issue that stirs passions in South Korea.

Mr Maehara urged efforts to build relations with South Korea, saying that he was struck during visits to Seoul by widespread opposition to officially pacifist Japan's consideration of allowing "collective self-defence" - or expanding its doctrine to assist the US in the event of an attack.

"I believe Prime Minister Abe, as far as he aims at changing the interpretation on collective self-defence, needs to explore every possible way to improve the relations with South Korea," he said.