Japan has marked the 70th anniversary of the end of the World War II under criticism from neighbours China and South Korea which said Prime Minister Shinzo Abe's speech failed to properly apologise for Tokyo's past aggression.

In a move likely to further strain relations with its neighbours, a pair of cabinet ministers visited the controversial Yasukuni shrine on Saturday, which neighbouring countries see as an ugly symbol of Tokyo's militarist past.

Memorial services on the day Japan surrendered to the Allies in 1945 come after nationalist Prime Minister Abe on Friday delivered a closely watched war anniversary speech that expressed regret but also said future generations need not apologise for Japan's war record.

His remarks were welcomed by the US but blasted by China as a non-apology, while Pyongyang derided it as "an unpardonable mockery of the Korean people" and South Korean President Park Geun-Hye said his speech "left much to be desired".

As part of Saturday's war memorials, Emperor Akihito, the son of wartime Emperor Hirohito, will deliver a speech with Abe and other cabinet ministers present.

Earlier, Haruko Arimura, minister in charge of women's empowerment, entered the gates of the shrine dedicated to millions of Japanese who died in conflicts - but also including more than a dozen war criminals.

Other politicians, including Sanae Takaichi, minister for internal affairs and communications, walked down the shrine's stone path Saturday morning.

The visits every August 15 - the anniversary of Japan's WWII surrender - enrage neighbouring nations, which view them as an insult and a painful reminder of Tokyo's aggression in the first half of the 20th century, including a brutal 35-year occupation of the Korean peninsula.

Both countries suffered badly from Japan's imperial march across Asia in the 20th century and wanted Abe to uphold previous explicit prime-ministerial apologies for Tokyo's actions.

The grandson of a wartime cabinet minister, Abe will not visit the leafy Yasukuni shrine on Saturday and sent a ritual offering instead, local media reported.

His late 2013 visit drew an angry response from Beijing and Seoul, as well as rebuke from close ally Washington.

Founded in 1869, the Shinto shrine honours some 2.5 million citizens who died in World War II and other conflicts, along with 14 indicted war criminals including General Hideki Tojo, who authorised the attack on Pearl Harbor, drawing the United States into the war.

They were secretly added to the Yasukuni honour list in 1978. This only became public knowledge the following year.

Japan's wartime history has come under a renewed focus since Abe swept into power in late 2012, his second stint as prime minister.

Much speculation had focused on whether he would follow a landmark 1995 statement issued by then-premier Tomiichi Murayama.

The so-called Murayama Statement, which became a benchmark for subsequent apologies, expressed "deep remorse" and a "heartfelt apology" for the "tremendous damage" inflicted, particularly in Asia.

On Friday, Abe - who has been criticised for playing down Japan's war record and trying to expand its present-day military - said future generations of should not have to apologise for the past.

"We must not let our children, grandchildren and even further generations to come, who have nothing to do with that war, be predestined to apologise," he said.