Tan Rong (left) sits in a voluntary blood donation vehicle on Shanghai's Nanjing Road on Jan 2 as a medical worker prepares to draw her blood.

The national health authority may introduce a new blood donation system to counter seasonal shortages reported by many local blood banks.

The proportion of non-remunerated voluntary donations has reached 99 percent since the country established the current system and enacted the blood donation law in 1998, Ministry of Health (MOH) figures showed. More than 11 million donations had taken place in the 11 years before 2009.

"However, there are still occasional blood shortages, especially during winters, which force the postponements of many medical operations," ministry spokesman Deng Haihua told a news conference on Monday.

The MOH is developing solutions, such as fostering a stable pool of regular donors, Deng said. This will improve the supply's reliability and safety, he said.

At present, about 60 percent of donors are university students and migrant workers, ministry figures showed.

But they cannot ensure a stable supply as they are mobile populations, and MOH regulations forbid cross-region blood transfers, experts said.