China has reported seven more Covid-19 deaths in Shanghai, as major firms such as Tesla forge ahead to resume production after a damaging weeks-long lockdown.

Supply chains have clogged and businesses have been forced to halt production in the metropolis of 25 million, as authorities cling to a zero-Covid approach to combat China's worst outbreak since the virus first emerged in late 2019.

Authorities have called for a “whitelist” of key industries and companies to be drawn up so production can continue, with over 600 firms identified for early work resumption in Shanghai, according to an AFP report.

The seven newly reported deaths were all unvaccinated patients, city health official Wu Qianyu told a press conference.