SHANGHAI: The Chinese city of Shanghai warned on Wednesday that anyone who violates strict COVID-19 lockdown rules will be dealt with strictly, while also rallying people to defend their city as its tally of new cases rebounded to more than 25,000.

The city police department spelled out the restrictions that most of the 25 million residents are facing and called on them to "fight the epidemic with one heart ... and work together for an early victory".

"Those who violate the provisions of this notice will be dealt with in strict accordance with the law by public security organs ... If it constitutes a crime, they will be investigated according to law," the department said in a statement.

The financial and commercial hub is under huge pressure to try to contain China's biggest COVID-19 outbreak since the coronavirus was first discovered in the city of Wuhan, some 800 km (500 miles) to the west, in late 2019.

Shanghai police also banned cars from the roads apart from those involved in epidemic prevention work or transporting people in need of emergency medical treatment.

They also warned increasingly frustrated residents, millions of whom are confined to their homes and struggling to get hold of daily supplies, not to spread false information or forge road passes or other clearance certificates.

Shanghai reported 25,141 new asymptomatic coronavirus cases for Tuesday, up from 22,348 a day earlier, and symptomatic cases also jumped to 1,189 from 994, city authorities said.

Shanghai's COVID measures, which reflect China's strict "zero-COVID" approach aimed at eliminating transmission chains, have reverberated through the global economy, with analysts warning they were not only hurting tourism and hospitality but also having an impact on supply chains across sectors.

At least 11 Taiwanese companies, mostly making parts for electronics, said on Wednesday they ere suspending production because of the disruption from China's COVID controls. 

However, the Caixin media group reported that Shanghai was one of eight cities involved in a pilot scheme to loosen quarantine requirements, citing a government plan set out in a document that has not been formally published.

The scheme began on Monday and will shorten centralised quarantine requirements from 14 to 10 days, Caixin said.

Relevant authorities were not immediately available for comment on the report.