A typhoon believed to be the strongest to hit southern China in four decades has killed eight people after claiming scores of lives in the Philippines, China's official news agency said.

Typhoon Rammasun was blamed for five deaths and 99 injuries after hitting Hainan island off China's southern coast on Friday, the Xinhua news agency reported.

Three people died later in the Guangxi region as the storm plowed into the mainland on Saturday on its way north to Vietnam.

Xinhua said the storm was believed to be the strongest to hit the region in 41 years. Wind speeds reached 216km/h with the storm knocking down power lines and damaging buildings, Xinhua said.

Authorities in southern China ordered the highest level of disaster alert and suspended hundreds of buses, trains and flights across the region. The typhoon had wreaked havoc earlier in the week in the Philippines, leaving 77 people dead.

Cities hit

The storm is expected to bring heavy rain throughout the weekend before moving southwest and weakening on Monday. Heavy rain is also expected over part of northern Vietnam.

The typhoon has hit several cities in the Chinese provinces of Guangxi, Guangdong and Hainan, tearing down trees and power lines and knocking out power grids.

In the Philippines, Rammasun badly hit the coconut-growing southern portion of the main island of Luzon, including the central Bicol region, which remained without power four days after it struck.

The storm damaged an estimated $134 million of crops and infrastructure, including roads and bridges.

Typhoons are common at this time of year in the South China Sea, picking up strength from the warm waters and dissipating over land.

Flooding across a large swath of southern China in the past week has already killed at least 34 people.