Nine hundred ships jammed before a navigation lock of a reservoir in south China's Guangxi Zhuang Autonomous Region amid falling water level caused by severe drought, local authorities said Saturday.

The waterway traffic jam started on Tuesday and the number of stranded ships had been increasing on Wuzhou City section of Xijiang River, said an official with the city's maritime affairs department.

The rapid drop of the reservoir's water volume due to the drought and the increased transport demand after the Spring Festival were behind the waterway jam, the spokesman added.

The provincial maritime authorities had limited the number to ships sailing toward the reservoir to less than ten ships a day, he said.

About 20 ships were let pass the navigation lock a day, he added.

The reservoir had increased the water discharge volume to ease the jam, the spokesman said.