The China branch of British drugmaker GlaxoSmithKline has been fined 3 billion yuan ($489 million) for paying bribes, a verdict that the firm said in a contrite statement it "fully accepts".

Changsha Intermediate People's Court in Hunan province ruled in Friday's closed-door trial that GSK China was guilty of "bribing non-government personnel" and then imposed the biggest ever by a Chinese court.

Five company employees were sentenced to two to four years in prison with reprieves.