BEIJING: Chinese authorities limited traffic flows on highways on Friday in several provinces after vehicles collided on icy patches as temperatures plummeted to below freezing across most of the country.

Temperatures will drop to as low as minus 40 degrees Celsius (minus 40 degrees Fahrenheit) in parts of the northeastern province of Heilongjiang and in the western region of Xinjiang, along with Inner Mongolia and the provinces of Gansu and Qinghai, according to forecasts from China's National Meteorological Centre.

The cold wave moving through the country from north to south is expected to drag temperatures lower into the weekend, even as Meteorological Centre says rain and snow will decrease.

In Henan province, snowfall and icy roads along with heavy fog caused multiple accidents on several expressways leading to traffic controls.

Traffic authorities in Ningxia province said some of its highways have become unsafe and implemented temporary traffic measures as snow fell.

Ferries and some buses were temporarily suspended early on Friday in Shanghai as the financial hub issued its first cold wave warning of the year as cold air from the north is forecast to reduce temperatures to as low as minus 6 C this weekend.

In the southwest, sections of many national and provincial highways in Tibetan cities such as Shigatse and Nyingchi were blocked due to snow, ice and low visibility as the skies have dumped snow since Monday.

The local government has mobilised 2,400 personnel, more than 3,300 metric tons of snow melting agent, and more than 23,000 cubic meters of anti-skid materials for prevention measures. Photos from state media show tractors scooping up snow and people shovelling on roads against a backdrop of white mountains.

China lifted its warning for blizzards before dawn on Friday but said heavy snowfall is forecast in parts of the northeastern Liaoning and Jilin provinces as well as in Shandong.

In the city of Shenyang in Liaoning province, authorities deployed 22,000 workers and over 3,400 machines for snow removal operations, clearing as much as 12,800 cubic metres of snow by early Friday. Its observatory has forecast snowfall and strong winds until Saturday.

The national forecaster said the scope and intensity of freezing rain will decrease on Friday but will still appear in some higher terrains in Guizhou and Hunan.