Torrential rains have left huge areas of Hubei and Zhejiang provinces under water, with more than one million acres of farmland hit, the official Xinhua News Agency said.
Almost 1,000 businesses have been forced to suspend operations and 5.7 million people have had their lives disrupted.
More than 7,000 homes collapsed or were otherwise damaged and direct financial damage was estimated at almost six billion yuan (572,566).
The downpour triggered a mudslide that buried houses and killed two people in Zhejiang's Changshan county, while two more were killed and two left missing by flooding in Hubei.
Flooding in eastern and southern China this month has left more than 170 people dead or missing.
Roads and railways are unusable but aid supplies are arriving.
Farmers quoted by Xinhua said the flooding was the worst in 20 years, reducing vegetable output by 20 per cent and also causing shortages of fruits and grains.
Prices for green vegetables were up 40 per cent, Xinhua said, adding to an inflation rate of 5.5 per cent, which is a three-year high.
The increase in the consumer price index reported last week was in line with expectations but higher than April's 5.3 per cent and March's 5.4 per cent.
The National Statistics Bureau said the main factor was an 11.7 per cent jump in food prices.
Higher food prices blamed on flooding were also reported in the eastern provinces of Anhui and Jiangxi, Xinhua said.
China is hit by flooding and drought every year.
The rain is expected to continue for the next two days, stretching from the financial hub of Shanghai in the east to rural Yunnan on China's south-west border.
Villagers on the outskirts of the city of Zhuji in Zhejiang returned to their homes yesterday as flood waters began to recede. Two towns were flooded and thousands were evacuated following the breach of two dykes in Zhuji on Thursday.
China has mobilised troops across the region to rescue stricken farmers and distribute food, but some villagers said the local government could have done more to prevent the flooding.
"When it first started, the breach (in the flood protection dyke] was not that huge - we could have easily fixed it," said 22-year-old villager Shou Qiongdan.
"But the government did not do anything. None of the local officials tried to salvage the situation. That's why we have such huge economic losses and so many people being affected by the flooding."In central China's Hubei, two people were killed after the Yangtze river and its tributaries burst their banks, with as many as three million people affected, Xinhua said. Further downstream in Anhui province, three died.