For Japan's neighbours the leafy Yasukuni shrine is a brutal reminder of Tokyo's imperialist past and wartime aggression, but for many ordinary Japanese it is merely a place to worship ancestors who died fighting for their country.

The controversial war memorial is a flashpoint in a bitter dispute between Japan and its Asian neighbours, particularly China and South Korea.

The long-simmering issue made international headlines this week when nearly 170 Japanese lawmakers made a pilgrimage there to mark a spring festival, angering Beijing and Seoul and sparking diplomatic protests.

Critics of the shrine point to the inclusion of the names of 14 war criminals among the 2.5 million honoured at the wooden temple, while the nationalistic museum on the site also draws fire.

For many, however, walking down Yasukuni's stone paths lined with cherry trees and past imposing gates dedicated to Shinto -- an animist religion with elements of Japanese history -- is part of a ritual far removed from politics.

Hideo Chikuni choked back tears as he explained that he had travelled more than 200 kilometres (125 miles) to honour his brother, a Japanese soldier who died during World War II.

"If you have lost family members, you would understand," the 65-year-old told AFP as a light rain fell.

"Japanese politicians visiting the shrine seem to cause all this controversy... but I don't think other countries have any business in this.

"People who are enshrined here suffered and died for the nation. They fought to protect Japan. And it is thanks to them that we live in a prosperous time today. We cannot forget that."

Yasukuni was originally built in 1869 to honour those who gave their lives for Japan and contains the names of soldiers who have fallen in armed conflicts including World War II.

But it also honours 14 men convicted of war crimes by a US-led tribunal after Japan's 1945 surrender, including General Hideki Tojo, the prime minister who authorised the attack on Pearl Harbor which drew the US into the war.

For foreign critics, the shrine is a stark reminder of Tokyo's brutal occupation of the Korean peninsula and imperialist expansion leading up to World War II.

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.

The site is presided over by Shinto priests and a ritual prayer that sees visitors clap and bow as they call on the spirits of ancestors adds a religious element, further complicating the site's reputation. Discussions about moving the memorial to a more secular location have gone nowhere.

Conservative Japanese lawmakers still routinely visit to pay their respects and underscore their ideological views, while liberal politicians tend to stay away.

Former prime minister Junichiro Koizumi prayed there once a year during his 2001-2006 tenure, enraging China and South Korea, but subsequent leaders have remained absent, including current premier Shinzo Abe.

Still, Abe has staunchly defended his colleagues' right to visit the site, and paid for equipment, bearing his name and title, which was used to decorate an altar.

In response China has insisted that "no matter in what capacity or form Japanese leaders visit Yasukuni Shrine, in essence it is an attempt to deny Japan's history of aggression through militarism".

South Korea on Thursday summoned Japan's ambassador to lodge a strong protest over the lawmakers' visit, and President Park Geun-Hye has warned Tokyo against shifting to the right and aggravating historical grudges.

"If (Japan) has a different perception of history and aggravates the scars of the past, it will be difficult to build future-oriented ties," she said this week.

Yuji Miyata, whose uncle is enshrined at Yasukuni, said he understands why the high-profile visits are a troubling reminder of the past for some, including a Chinese man who unsuccessfully tried to burn it down in 2011.

But Miyata, a 48-year-old businessman, said most of the shrine's five million annual visitors come to honour fallen ancestors and pray for peace.

"I can understand why foreign politicians are critical," he said. "They may see this in the context of the Japanese empire invading other countries.

"But for us, the general public, we don't think about those things when we come here, we just pray for our relatives who died."