Japanese Prime Minister Shinzo Abe is to deliver a war anniversary statement Friday that neighbouring nations, particularly China and South Korea, will scrutinise for signs of sufficient remorse over Tokyo's past militarism.

The words that Abe chooses to mark the 70th anniversary of the end of World War II carry symbolic importance and could set future relations with countries that suffered from its brutal march across Asia.

Any attempt to tone down explicit apologies made by previous leaders could anger China and Korea.

The statement from Abe is expected early Friday evening after a cabinet meeting.

The 60-year-old nationalist -- criticised by some for playing down Japan's wartime record and trying to expand the role of the military -- has not specified what he will say on the eve of the anniversary of Japan's surrender to the Allies in 1945.

The issue has been top news in Japan, with public broadcaster NHK reporting this week that an original draft of Abe's statement included the words "apology" and "aggression", in a possible concession to Beijing and Seoul.

Those words appeared in a landmark 1995 statement by then-premier Tomiichi Murayama, who expressed "deep remorse" and a "heartfelt apology" over Japan's actions.

The so-called Murayama Statement, which became a benchmark for subsequent leaders' apologies, said Japan "through its colonial rule and aggression, caused tremendous damage and suffering to the people of many countries, particularly to those of Asian nations".

Abe himself has said only that he would express remorse and follow previous prime ministerial apologies "as a whole".

But Japan's prime minister has repeatedly talked of the need for what he calls a "forward-looking attitude" that concentrates on the positive role his pacifist country has played in Asia since its surrender in 1945.

He has made waves by quibbling over the definition of "invade" and provoked anger by downplaying Tokyo's formalised system of sex slavery in military brothels.

A 2013 visit to Yasukuni Shrine -- seen by Japan's neighbours as a potent symbol of its militarist past -- sent relations with Beijing and Seoul to their lowest point in decades, earning a rebuke from close ally Washington and aggravating simmering territorial disputes.

While Abe's nationalism tends to be popular on the political right, Japan's own national self-narrative has over the decades become one more of victim of the US atomic bombings than colonialist aggressor largely responsible for an ill-fated Pacific conflict.

China says more than 20 million of its citizens died as a result of Japan's invasion, occupation and atrocities, while Tokyo colonised the Korean peninsula for 35 years until 1945.

Last week, a panel set up to advise on the wording of Abe's statement was unambiguous.

Japan "caused much harm to various countries, largely in Asia, through a reckless war," it said.

"The responsibilities of the Japanese government and military leaders from the 1930s and beyond are very serious indeed."