More than 18.5 million hectares of wheat, or 80 percent of the total planted area of the crop in China, had been harvested by Saturday, the Ministry of Agriculture said.

The ministry said more than 80 percent of the crop had been harvested by machines.

The harvest in Shandong Province, which was earlier hampered by diesel shortages, accelerated as more supplies arrived. Farmers in the province have cleared about 75 percent of the wheat fields.

But heavy rain hampered work in Hebei Province.

Jiangsu Province in the south has almost finished harvesting, and now it is time to reap the wheat crop in northern regions including Tianjin and Beijing, the ministry said. Wheat is grown in some remote parts of greater Beijing, which extends far beyond the center city.

The exact size of the harvest is not yet known, as the grain must be processed. However, Agriculture Minister Sun Zhengcai in late May expressed optimism for a good harvest, saying total output would rise for a fifth consecutive year.

Summer crops usually account for about 23 percent of the nation's annual grain output. Last year, China produced more than 500 million tons of grain.

Guo Gengmao, head of central Henan Province, which produces more than a quarter of China's wheat, said in early June the province's harvest was expected to hit a new high of 30 million tons this year.