China has granted conditional approval for its second COVID-19 vaccine, ahead of the expected emergency approval from the WHO for two of its jabs that would enable the country to step-up global supplies of the shots.

China's drug regulator has given approval for the conditional mass use of the coronavirus vaccine produced by Chinese pharmaceutical firm Sinovac Biotech.

Sinovac Biotech announced on Saturday that CoronaVac, an inactivated vaccine candidate against COVID-19, received authorisation from the National Medical Products Administration for conditional mass use in China.

It is the second locally-made vaccine to be given conditional approval. Beijing authorised the state-owned Sinopharm's vaccine in December.

The conditional approval was based on the results of the overseas Phase-III clinical trials of CoronaVac. Final data from the trials has not been made available yet and the results of its efficacy and safety require further confirmation, state-run Global Times said, quoting a Sinovac statement.

The World Health Organisation (WHO) on Friday said two Chinese vaccines are "in a very advanced stage" of its Emergency Use Listing Procedure (EUL) assessment.

The vaccines, produced by Sinovac and Sinopharm, are among the four vaccines in very advanced phase of approval, Mariangela Simao, assistant WHO Director-General for Access to Medicines, Vaccines and Pharmaceuticals, said in Geneva.

A team of experts from the WHO are now already in China, and they "will start inspections next week" as they are currently in quarantine, she said.

So far, only the Pfizer-BioNTech vaccine has received EUL approval. Two other vaccines -- Britain's AstraZeneca and South Korea's SK Bioscience -- are also being assessed, Simao said.

According to WHO, 238 candidate vaccines are being developed worldwide -- 63 of them in clinical trials in various countries.

China is currently testing 16 vaccines which are in different stages of trials. It has vaccinated over 32 million people at home so far.

China has offered to provide 10 million COVID-19 vaccines to COVAX, a global initiative, which aims at ensuring that middle and lower-income countries get timely access to coronavirus vaccines.