BEIJING (Reuters) - Constant rains in recent weeks have delayed wheat planting in main production regions in China, a government official said on Wednesday.

China had completed 26% of winter wheat planting across the nation by Oct. 19, slower by 27 percentage points than normal years, due to constant rains since September, according to Pan Wenbo, head of the planting management division under the Ministry of Agriculture and Rural Affairs.

The ministry will take "extraordinary measures" to tackle the "unfavourable impact and austere challenges" the rains have posed for harvest and planting, Pan said during a press briefing.

China's cabinet, the State Council, on Wednesday said authorities would work to ensure a "bumper" summer grain harvest next year, state broadcaster CCTV reported.

Measures taken to achieve this include doing a good job in drying and stockpiling grain, as well as in autumn and winter planting, CCTV said in its evening newscast after a State Council meeting chaired by Premier Li Keqiang.

Other measures include speeding up drainage of farmland, increasing supply of fertiliser and pesticides, and ensuring supply of electricity and diesel for grain drying, the report said, adding flood-hit areas will be entitled to disaster relief funds.

Pan's comments came as Beijing renewed a policy focus on food security following the COVID-19 pandemic and after prices of corn, the other main grain crop in China, soared on falling inventories and output, pushing up feed use of wheat and grains imports to record high levels.

"It is still hopeful that we will win a bumper harvest (of wheat next year) as long as we can plant before winter and follow up with proper management measures in the spring," Pan said.

Late planting would affect growth, while too much moisture in the land would cause more diseases for the crop, Pan added.

China has raised the minimum purchase price for wheat in 2022, part of an effort to enhance grain security, by bolstering farmers' interest in growing the grain.

The rains have also delayed harvest of autumn grains, which mainly include corn, soybeans and middle-late season rice, by 4 percentage points compared with normal years, and pushed up cost, Pan also said.

Heavy rains hit the corn harvest in northern China and damaged quality of the new crop, leading a government think tank to lower its estimates on China's 2021/22 corn output.

The rains mostly affected Huang-Huai-Hai river areas and northwestern China with limited impact on other main production regions including northeastern and southern China, Pan added.

Autumn grains output in total was set to rise, thanks to increased acreage, and more planting of high-yield corn, according to Pan.

(Reporting by Hallie Gu and Shivani Singh Additional reporting by Tom Daly Editing by Elaine Hardcastle and Mark Potter)