A major rescue effort is under way after a boat carrying 458 passengers capsized in China's Yangtze River.

The Eastern Star ship is reported to have sunk rapidly at around 9.28pm local time in the Jianli section of the river.

Seven people have managed to swim to shore and a total of 20 have been rescued in what could be one of China's worst shipping disasters, according to The People's Daily newspaper.

Among those on board the Eastern Star were 47 crew and 406 tourists aged between 50 to 80 that were on a trip organised by a Shanghai tour group, the paper said.

Those rescued include the ship's captain and engineer, who said the vessel sank quickly after being caught in a storm.