BEIJING, Oct 31 (Reuters) - Chinese Premier Wen Jiabao on Saturday warned the country faced an "extremely grim" job to prevent the spread of the H1N1 flu strain, calling on more people to be vaccinated and for vaccine production to be raised.

"At present, the flu prevention situation is extremely grim and there may well be outbreaks or it may spread in certain areas," Wen told officials during a visit to a Beijing children's hospital, in comments carried on state television.

People must be "encouraged to get vaccinated as soon as possible" and "research into and production of vaccines must be stepped up", he added.

Television pictures showed Wen, a mask tied over his face, talking to children, parents and workers at the hospital.

Health Minister Chen Zhu warned in September that China faced a serious situation in containing the disease as schools start up again and the number of cases rises..

China has to date reported 44,981 H1N1 infections, including six deaths, the latest of which was reported on Saturday in the northeastern province of Heilonjiang.

State news agency Xinhua added that a cold snap bearing down on northern China could heighten the flu risk.

But Wen also struck a note of optimism. "We have complete confidence, and the ability to carry out prevention work well and to prevent outbreaks. We must work as hard as possible to reduce the number of serious cases and deaths," he said.

There are already strict checks at border crossings and many places where crowds gather like karaoke parlours, and the government began a mass vaccination programme in late September, starting with around 100,000 students in Beijing.

Health Minister Zhu said at the time that the government aimed to produce 26 million doses of vaccine by the end of October, and 65 million doses by the end of 2009.

China's Sinovac reported last month that its vaccine protected patients with a single dose.