Conservative Japanese Prime Minister Shinzo Abe broke with two decades of tradition Thursday by omitting any expression of remorse over Japan's past aggression in Asia on the anniversary of its 1945 surrender.

Abe's speech — which came after nearly 100 lawmakers, including two Cabinet ministers, visited a controversial war shrine — avoided typical words such as "profound remorse" and "sincere mourning" to atone for those who suffered as Tokyo's imperial army stormed across East Asia.

The omission was sure to anger China and South Korea, which have bristled at Abe's talk of overhauling Japan's pacifist constitution, while visits to the Yasukuni shrine enrage neighbours who see its as a symbol of Tokyo's imperialist past.

Abe also avoided a promise typically given by past Japanese premiers to "uphold [Japan's] pledge not to engage in war."

"I will never forget the fact that the peace and prosperity we are enjoying now was built based on the sacrifice of your precious lives," Abe said in a reference to the 2.5 million war dead honoured at the shrine.

Yasukuni shrines marks citizens who died in World War II and other conflicts, including 14 top convicted war criminals, such as General Hideki Tojo who authorised the attack on Pearl Harbor, which drew the United States into the war.

Japan surrendered 15 August 1945 after the United States dropped atomic bombs on the cities of Hiroshima and Nagasaki.

Visits to the Yasukuni site by Japanese politicians angered neighbouring nations, which view them as 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.

Abe, who was expected to stay away from the shrine Thursday but who reportedly sent a ritual offering via an aide, added in his speech that Japan would do its "utmost" to ensure "permanent world peace."

Security was tight with hundreds of police surrounding the leafy shrine in the heart of Tokyo, as right-wing nationalists carried flags calling on visitors to pray for Japan's "heroic war dead."

Yoshitaka Shindo, internal affairs and communications minister in Abe's Cabinet, made an early morning visit followed by about 90 other lawmakers later in the morning.

"It was my personal decision to come here," Shindo told reporters, adding it was a "private" matter that should not affect Japan's diplomatic relations.

Another Cabinet member, Keiji Furuya, also made the trip.

"Consoling the souls of war dead is a purely a domestic issue," Furuya told reporters.

"This is not something that other countries are supposed to criticise or interfere with."

Abe gave a ritual offering earlier this year when nearly 170 lawmakers visited the shrine for a spring festival, grabbing international headlines and sparking diplomatic protests.

On Tuesday, Seoul lashed out ahead of this week's anniversary, saying "our government and people will never tolerate such visits."

"We once again stress that there should be no trips by top Japanese politicians to the Yasukuni shrine," South Korean foreign ministry spokesman Cho Tai-Young told reporters.

Even at home there is significant opposition to Yasukuni, including among some relatives of those honoured there, who say it glorifies war and the darker chapters in Japan's history.

For many, however, walking down the shrine's stone paths lined with cherry trees and past imposing gates dedicated to Shinto — Japan's animist religion — is part of a ritual far removed from politics.

"My father held me only once before heading to the war zone, knowing Japan would lose," 69-year-old Sumiko Iida told AFP Thursday.

"I'm absolutely against wars," Iida added.

Chinese state media Wednesday reported Abe's decision, relayed by Japanese press and government sources, not to visit the "notorious" shrine.

Earlier in the week, the 35th anniversary of Japan and China normalising diplomatic relations passed quietly. Ties remain frosty following maritime skirmishes over a set of East China Sea islands that are disputed by both countries.

Observers have warned that the contested islands, which are believed to harbour mineral resources beneath their seabed, could be the flashpoint for military conflict between the two Asian giants.

Tokyo is locked in a separate territorial dispute with Seoul.

Abe has mostly focused his attention on reviving Japan's economy since sweeping December elections, but he has also mulled changing the pacificist constitution imposed on Japan by the United States and its allies after the war.