BEIJING - ?China is faced with severe challenges in collecting enough blood plasma to produce medicines, Health Minister Chen Zhu said Sunday.

Chen called on the public to join blood donation after donating blood plasma at the Beijing Red Cross Blood Center on Sunday, the fifth time since he took office in 2007.

Blood plasma is needed to make blood products like prothrombin complex which is vital for hemophiliacs.

The total volume of blood plasma collected last year was 4,180 tonnes, while the volume needed to produce enough medicines was 8,000 tonnes, said a statement from the ministry. The situation became even worse this year.

Donations of blood plasma in China fell dramatically in recent years, as a result of safety concerns from donors and the government's efforts to regulate blood collection after contamination triggered HIV infection scandals.

In an overhaul of plasma collection services in 2004, the ministry closed 262 donation centers, leaving only 138 in operation, resulting in the plasma donations falling at least one-third from 5,000 tonnes in 2003.

Blood plasma are currently collected at 144 designed stations across the mainland. The stations, as requested by law, are all owned by major manufacturers of blood products.

Chen promised to encourage qualified drug makers to set up more collection stations in the next five years.

He also assured the public the safety of blood donation at authorized stations.