China's southern coast is suffering the worst outbreak of the 'red tide' algae in its history, according to China's official media.

The China Daily newspaper said that the algae bloom, which devastated the fishing industry in neighbouring Hong Kong over the past week, has engulfed a stretch of Guangdong's coastal waters.

The algae is said to have killed 350 tons of fish in China and caused economic losses of more than $4m.

It kills fish by invading their gills and suffocating them.

Composed of microscopic organisms, the algae multiplies rapidly, reducing oxygen in the water and turning it a reddish brown colour.

Normally, red tides affect the waters off Guangdong between May and June but this year they are earlier and more severe than ever before.

China's Xinhua news agency said local fishermen were fighting the advance of the algae day and night and trying to save fish by adding oxygen to the water.

The provincial government has sent officials to help but the China Daily newspaper said their efforts were hampered by a shortage of funds.

In Hong Kong, the red tide has already killed at least 1,500 tons of farmed fish, with fish farmers estimating their losses at $32m.