China's state media on Friday urged "excessive" counter-measures after Japanese Prime Minister Shinzo Abe's inflammatory war shrine visit, as analysts warned against the dangers of provoking smouldering regional resentments.

The comment came after China summoned Tokyo's ambassador on Thursday to deliver a "strong reprimand" after Abe paid respects at the Yasukuni shrine earlier in the day.

The site honours several high-level officials executed for war crimes after World War II, a reminder of Japan's 20th century aggression and a source of bitterness for China and other Asian countries.

South Korea, which also has a litany of historical resentments against Japan, slammed Abe's visit as "anachronistic behaviour." And the United States -- Tokyo's key security ally -- issued a rare criticism, saying it was "disappointed" over an act "that will exacerbate tensions with Japan's neighbours".

The Global Times, a paper that is close to China's ruling Communist Party and often strikes a nationalist tone, said that people were "getting tired of... futile 'strong condemnations'".

"China needs to take appropriate, even slightly excessive countermeasures" or else "be seen as a 'paper tiger'", it warned in an editorial.

It suggested barring high-profile Japanese politicians and other officials who went to the shrine from visiting China for five years.

The visit sparked protests Friday in both Seoul and Hong Kong, the former British colony which was occupied by the Japanese during the Second World War.

In Seoul demonstrators, most of whom were in their 60s and 70s, shouted anti-Japanese slogans such as "Down with Abe!" and "Boycott Japanese goods!" outside the country's embassy.

Brief scuffles erupted when police tried to stop the burning of Japanese flags but there were no injuries or arrests.

Similar scenes broke out in Hong Kong where protestors burned Japanese military flags emblazoned with the Chinese words for "shame", a picture of Japanese Second World War general Hideki Tojo and a portrait of Abe.

Analysts said the visit showed Abe's determination to drag Japan, constrained by a US-imposed "pacifist" constitution that he wants to change, to the right and nudges Northeast Asia a significant step closer to conflict.

China and Japan, the world's second- and third-largest economies, have important trading ties.

But tensions over East China Sea islands known as Diaoyu in China and Senkaku in Japan have soured diplomatic relations since last year.

Chinese protesters took to the streets in major cities at that time, attacking Japanese diplomatic facilities and businesses, harassing individual Japanese and turning over vehicles made by the country's manufacturers in demonstrations initially condoned by authorities, who eventually restricted them.

Beijing has pursued its territorial claims more assertively in recent years and last month unilaterally declared an "air defence identification zone" that included the islands, provoking widespread diplomatic condemnation of its own.

In a commentary on Abe's visit, the PLA Daily, the newspaper of China's People's Liberation Army, said it "once again exposed the impunity of Abe on the rightist road and also conveys a very dangerous signal".

Those enshrined at Yasukuni were "devils, butchers, and executioners who were drenched in blood and brought havoc to hundreds of millions of people in Asia", it said.

"Abe not only trampled on human conscience, but insulted the IQ of people in the victim countries."

Abe was the first incumbent Japanese prime minister to visit the site since 2006.

The strength of Chinese reactions reflect still smouldering resentment against over the devastation it suffered at Japan's hands during the Second World War.

According to estimates by Chinese government researchers, China lost 20.6 million people directly from the conflict.

Analysts also say, however, that China's ruling Communist Party has been adept at using outrage against Japan to deflect criticism away from its own rule.

The party mouthpiece, the People's Daily, drove home in a commentary its view that Japan appears incapable of understanding its part in the war.

"History tells people that one country which cannot correctly understand the evil fascist war, nor reflect on war crimes, cannot truly achieve national rejuvenation," it said.

Jia Qingguo, an international relations expert at Peking University, described Abe as reckless and misguided.

"I think he's very irresponsible," Jia told AFP. "He knows the negative consequence of this for China-Japan relations."

"Maybe it's what he really believes in his mind, that is the history of the Second World War has been misinterpreted by the rest of the world, what Japan did was the right thing."

China's foreign ministry spokeswoman Hua Chunying said Friday that the Japanese leader's argument that it was a private visit was "feeble and not worth refuting".

"What we see is hypocrisy and self-contradiction," she added, but declined to be drawn on specific measures China might take.

Trying to limit fallout from the visit, Abe said Thursday it should be seen as a pledge that Japan would not go to war again and was not intended to hurt Chinese or South Koreans.