China warns citizens amid Vietnam protests - Source AAP

Over 100 protesters have been arrested in central Vietnam after taking to the streets to stand against a plan to open new economic zones for foreign investment.

China has warned its citizens in Vietnam after protesters clashed with police over a government plan to create new economic zones for foreign investment that has fuelled anti-Chinese sentiment in the country.

More than 100 protesters were arrested and dozens of police injured at a protest in central Vietnam on Sunday, one of several demonstrations nationwide against the special economic zones opponents fear will be dominated by Chinese investors.

The Chinese embassy in Hanoi posted a notice on its website referring to the protests as "illegal gatherings" that had included some "anti-China content".

"The Chinese embassy in Vietnam is paying close attention to the relevant developments and reminds Chinese citizens in Vietnam to pay attention to security when travelling," the notice said.

Vietnam's National Assembly agreed on Monday to delay a vote on the draft bill, which would allow foreign investors to lease land for up to 99 years and provide greater incentives and fewer restrictions than at present in the country.

Nguyen Thi Kim Ngan, chairwoman of the Assembly, said the protesters might have misunderstood the nature of the bill.

"People should stay calm, believe in the decisions of the party and the state, especially in the fact that the National Assembly is always listening to the people's opinions when discussing the bills," Ngan said.

Public protests are not rare in Vietnam and are often quickly quelled by the police.

On Sunday, protesters in the central province of Binh Thuan threw petrol bombs and bricks at police and damaged local government offices and vehicles, state media reported.

Police arrested 102 protesters, the online newspaper VnExpress reported on Monday, citing local police. The report said dozens of policemen were injured in the incident.

In the capital Hanoi, police detained more than a dozen protesters who marched down a busy street, some carrying anti-Chinese banners including one that said "No leasing land to China even for one day".