Vietnam on Monday accused a Chinese vessel of firing on one of its fishing boats in disputed waters, denouncing the incident as a "serious violation" of its territorial sovereignty.

The Vietnamese boat was fishing near the contested Paracel Islands last Wednesday when it was "chased and shot at by a Chinese vessel, causing a fire in the cabin," foreign ministry spokesman Luong Thanh Nghi said.

"Vietnam strongly protests, urging China to investigate and seriously deal with the wrongful and inhumane act and compensate Vietnamese fishermen for their loss," Nghi said in a statement on the ministry's website.

It did not say what kind of Chinese vessel was involved.

Vietnam and neighbouring China have a long-standing territorial disputes over the Spratly and Paracel Islands, which both countries claim, and often trade diplomatic barbs over oil exploration and fishing rights.

In recent years, China has begun aggressively patrolling around the contested islands, using fishing bans and patrol boats to keep foreign trawlers out, according to Vietnamese officials and fishermen.

Hanoi says hundreds of fishing boat crews have been arrested by Chinese authorities over the last few years.

Beijing has occupied the Paracels, known as Xisha in Chinese, since a brief war with South Vietnam in 1974, and also claims the Spratlys, as do -- in whole or in part -- Taiwan, Malaysia, the Philippines and Brunei.

Beijing claims as its historical territory virtually all of the South China Sea, which is believed to sit atop huge oil and gas reserves as well as being home to important fishing grounds.