The worst-hit Minqing County in Fuzhou, capital of Fujian, has reported 73 deaths, with another 17 still missing, state-run Xinhua news agency reported.
Typhoon Nepartak, the first to hit this year, made landfall in Fujian Province on July 9.
With this total casualties in recent rains and floods in China floods in several provinces rose to 309.
The total number of missing in the last few weeks stand at 112.
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Around 200 residents from two districts in Wuhan City had been transferred prior to and after the breach, which happened at a flood detention basin, the local flood control office said.
More than 1,000 rescuers have been dispatched to the scene.
Over 70 people have been rescued so far who were trapped by the rising flood waters.
The area has cut off power and natural gas supplies while preparations are being made to fill the breach, according to a media report.