Beijing plans to send a survey team to land on small East China Sea islands at the centre of a bitter territorial dispute with Japan, state media reported Tuesday, in what would be a major escalation of the row.

Chinese marine surveillance vessels regularly patrol what Beijing says are its waters around the Diaoyu islands, prompting accusations of territorial incursions by Tokyo, which controls the outcrops and refers to them as the Senkakus.

Activists from Taiwan and Hong Kong have landed on the islands, which Taipei also claims, but no representative of the Beijing government has sought to do and any attempt would be seen as highly provocative.

The website of China National Radio reported the plan, citing an interview with Li Pengde, deputy head of the National Administration of Surveying, Mapping and Geoinformation.

Li said he wanted to carry out the survey "under conditions where the safety of the survey team can be guaranteed", the report quoted him as saying.

He did not say when the unit would be dispatched but the report cited him as saying it would be as soon as possible.

Li said a survey was needed as there were limits to map-making from aerial images.

Tokyo would be likely to try to prevent any Chinese government survey. The Japanese coastguard has stopped some civilian activists from landing, while others were arrested after raising Chinese flags on the islands.

As the dispute has escalated, both sides have scrambled jets to ward off moves by the other and in February Japan alleged a Chinese frigate had locked its weapons-targeting radar on one of its destroyers. Beijing denied the accusation.

The report on the cartographical plan comes after state media in January quoted a mapping administration official as saying China intended to survey the islands.

That official, however, alluded to "difficulties in landing on some islands" due to their being occupied, although Japan was not mentioned by name.

Beijing is also at odds with several Southeast Asian countries, including the Philippines, over islands in the South China Sea.