Japan told China on Wednesday its ships must stop violating Japanese territory in the East China Sea after a long-standing maritime row intensified this month.

The admonition came in a meeting between Japanese Foreign Minister Fumio Kishida and his Chinese counterpart Wang Yi.

The two countries are locked in a dispute over uninhabited islands controlled by Japan as the Senkakus but claimed by China as the Diaoyus.

Tensions have waxed and waned though rose this month as Japan grew angry over what it said were numerous incursions into waters around the islets by Chinese ships.

Tokyo has lodged more than two dozen protests through diplomatic channels since August 5, saying there have been repeated "intrusions" by Chinese coastguard vessels.

"I strongly asked him to completely quieten the situation, prevent it from occurring again and improve the overall environment in the East China Sea," Kishida told reporters after meeting Wang.

At one point Japan reported more than 200 Chinese fishing boats operating near the islands and said there was cooperation between some of them and coastguard vessels.

Kishida quoted Wang as saying that China would control the situation.

Wang, however, in separate remarks to reporters, said he and Kishida had extensive talks but suggested the issue had been blown out of proportion.

"It is related both to the fishing season, but also hyped by the media," said Wang, a former Chinese ambassador to Japan.

"The situation has now returned to normal."

He added that the two sides agreed to "make efforts to resolve our maritime dispute" as well as launch "as soon as possible" a previously discussed mechanism to prevent accidents at sea and air.

Increased patrols by ships and aircraft from the two sides around the rocky islets have periodically raised fears of accidental armed clashes.

Tokyo and Beijing in November 2014 agreed on a four-point accord to improve their relationship, which had soured to its worst in years over the island dispute and other issues.

Contacts have increased but relations remain marked largely by tension and distrust.

Kishida also said that if the situation in the East China Sea improves, Japan would like to step up dialogue with China -- including at next month's G20 summit in Hangzhou to be attended by Chinese President Xi Jinping and Japanese Prime Minister Shinzo Abe.

Wang's visit is the first by a Chinese foreign minister to Japan since Xi became president in March 2013.

"We have to work to improve the Sino-Japanese relationship," he said upon arrival.

Earlier on Wednesday, Wang, Kishida and South Korean Foreign Minister Yun Byung-Se held trilateral talks at which they discussed regional issues such as North Korea.

They also reaffirmed a leaders' summit would be held later this year in Japan, though no date was announced.