BEIJING >>More than 40 miles of dikes are in danger of overflowing in an eastern Chinese province where floods have caused $1.2 billion in losses, authorities said Monday as the country neared a critical point in battling seasonal rains.

Heavy rains pounded Zhejiang province over the weekend, and the level of a river that passes through Lanxi city has risen sharply, said Zhao Fayuan, deputy director of the provincial flood control headquarters.

The level of Lanjiang river has now hit 110 feet, the highest since 1966, the headquarters said.

Several sections of the dikes in Lanxi city are barely holding, Zhao said. More than 20,000 people could be affected if the dikes are breached, he was quoted as saying by the Xinhua News Agency.

The flood control headquarters advised Lanxi officials to evacuate all residents near the dikes that are at risk of overflowing, and to repair them immediately.

Recent flooding has destroyed 600,000 acres of farmland and caused 1,846 companies to stop production in Zhejiang, incurring 7.69 billion yuan ($1.19 billion) in direct economic losses, the flood control agency said. Of these, 3.4 billion yuan were agricultural losses. Coastal Zhejiang is one of China’s richest provinces and its economy grew 11.8 percent last year.

Flooding in eastern and southern China this month has triggered landslides, cut power and telecommunications and left more than 180 people dead or missing. Five more people were killed Sunday and one remains missing after surging floodwaters swept them away in their southwest villages, Xinhua reported.

China’s minister for water resources said Sunday that the country was entering a crucial period for flood control as severe floods triggered by heavy rains threatened southern areas.

It is likely that more frequent and more intense downpours will continue, Chen Lei told a meeting in Beijing, Xinhua reported.

He urged local authorities to improve weather forecasting and ensure dikes, reservoirs and dams are safe.

China’s national weather agency said Monday that torrential rains will continue in southern and eastern areas for the next three days.

However, while the deadly flooding continues, a persistent drought is still plaguing five provinces in the middle and lower reaches of the Yangtze River. It has left 630,000 people without safe drinking water and affected 11.9 million acres (4.8 million hectares) of farmland, Chen said.