China has put its homegrown coronavirus vaccines on display for the first time, as the country where the contagion was discovered looks to shape the narrative surrounding the pandemic.

High hopes hang on the small vials of liquid on show at a Beijing trade fair this week -- vaccine candidates produced by Chinese companies Sinovac Biotech and Sinopharm.

Neither has hit the market yet but the makers hope they will be approved after all-important phase 3 trials as early as year-end.

A Sinovac representative told AFP his firm has already "completed the construction of a vaccine factory" able to produce 300 million doses a year.

On Monday, people at the trade fair crowded around booths showing the potential game-changing vaccines.

China, which is facing a storm of foreign criticism over its early handling of the pandemic, has been trying to repurpose the story of Covid-19.

State media and officials are now emphasising the revival of Wuhan, the central Chinese city where the deadly pathogen surfaced, as a success story in the fight against the virus.

They are also touting progress on domestic vaccines as a sign of Chinese leadership and resilience in the face of an unprecedented health threat that has pummelled the global economy.

In May, President Xi Jinping pledged to make any potential vaccine developed by China a "global public good".

The potential vaccines on display are among nearly 10 worldwide to enter phase 3 trials, typically the last step ahead of regulatory approval, as countries race to stub out the virus and reboot battered economies.

Sinopharm said it anticipates the antibodies from its jab to last between one and three years -- although the final result will only be known after the trials.

China's nationalistic tabloid Global Times reported last month that "the price of the vaccines will not be high".

Every two doses should cost below 1,000 yuan ($146), the report said, citing Sinopharm's chairman, who told media he has already been injected with one of the candidate vaccines.

China's official Xinhua news agency reported Monday that another vaccine candidate, developed by Chinese military scientists, can deal with mutations in the coronavirus.

As of last month, at least 5.7 billion doses of the vaccines under development around the world had been pre-ordered.

But the World Health Organization has warned that widespread immunisation against Covid-19 may not be on the cards until the middle of next year.