TAIPEI (AFP) - Vietnam's de facto ambassador to Taiwan on Friday gave a "personal" apology after anti-China protesters ravaged hundreds of Taiwanese factories in his country this week, and said some 1,000 people have been arrested over the violence.

Two Chinese workers were killed and more than 100 injured in Vietnam's worst anti-China unrest in decades. The violence was sparked by Beijing's deployment of an oil rig in the resource-rich South China Sea, the centre of a territorial row between Vietnam and China.

"A small number of law-breakers damaged and set fire to Taiwanese businessmen's factories and caused panic... I personally expressed regrets and apologies," Bui Trong Van said, speaking in Mandarin.

"Riot police cracked down on (the protesters) and the riots were eased. So far the Vietnamese government has arrested more than 1,000 people and quickly indicted them," he said in a televised press conference in Taipei.

The Vietnamese envoy added that a local official has promised to "discuss appropriate measures to help resolve Taiwanese businessmen's losses", and urged Taiwanese media not to sensationalise the unrest.

"I hope Taiwanese media will not overly exaggerate as this would cause panic and is bad for the ties between Taiwan and Vietnam."

Vietnam, like most countries, officially recognises China over Taiwan, a self-governing island which Beijing regards as part of its territory awaiting reunification.

Taiwan's government has expressed serious concerns over the unrest, and demanded Hanoi fully compensate the hundreds of Taiwanese companies that were damaged.

Taiwan is Vietnam's fourth biggest foreign investor after Japan, South Korea, and Singapore, with Taiwanese companies plunging US$27.3 billion (S$34.2 billion) into the communist country from 1988 to 2014.