Chinese President Xi Jinping on Wednesday held talks with a top Vietnamese envoy and said the two countries should repair strained relations, state media reported.

Xi met Le Hong Anh, a member of Vietnam's Communist Party politburo, the state-run Xinhua news agency said. It described him as being sent by the head of the country's Communist Party.

China and Vietnam, once close ideological allies, are locked in a bitter dispute over disputed waters and island chains in the South China Sea.

"A neighbour cannot be moved away and it is in the common interests of both sides to be friendly to each other," Xi said during the meeting, according to Xinhua's brief dispatch.

In May Beijing moved a deep-sea oil rig into waters that Hanoi claims, sparking deadly anti-China riots in Vietnam and triggering a high-seas standoff around the rig.

China in June dispatched State Councillor Yang Jiechi, its top foreign policy official, to meet Vietnamese officials in Hanoi though the two sides made no progress in easing tensions.

Beijing removed the rig in July, claiming its mission was successfully completed.

Xi, who is separately head of China's Communist Party, also stressed that the two nations are not only close neighbours but also socialist countries, Xinhua said.

Anh arrived in Beijing on Tuesday for a two-day stay.

He also met Liu Yunshan, a top Communist Party official and "they agreed to avoid actions that might worsen their disputes on maritime issues", the report said.

China claims nearly all of the South China Sea, even waters approaching the coasts of its neighbours, and has become increasingly assertive in staking those claims.

Vietnam, the Philippines, Brunei, Malaysia and Taiwan have competing claims to parts of the sea.

Vietnam's authoritarian leaders have struggled to balance traditionally warm ties with fellow communists in Beijing with widespread anti-China sentiment among the population.

Despite decades of political closeness, the two sides fought a brief but bloody war in 1979 triggered by Vietnam's invasion of Cambodia.