Shanghai, set to officially emerge from a lockdown on June 1, has been cautiously easing COVID-19 curbs, allowing more of its population to venture out and putting more cars and vehicles back on its once busy streets.

Officials in the city on Thursday said students in junior and senior high school can return to offline classes from June 6, following word earlier in the week that shopping malls and department stores will be allowed to reopen, although in batches, from June 1.

The city of 25 million people reported on Thursday it had 338 new locally transmitted infections for May 25, the lowest since mid-March and a far cry from tens of thousands at the peak of its outbreak in April.

China's biggest city by economic output has suffered due to the lockdown imposed in early April. Other cities not under lockdown but still hit by stringent measures, including the capital Beijing, have also struggled to keep their local economies upright.

Offering a grim view of the world's second-biggest economy, Premier Li Keqiang on Wednesday said economic difficulties in some aspects were even bigger than in 2020 when the country was first hit by the outbreak.

Many private-sector economists expect gross domestic product to contract in April-June from a year earlier versus the first quarter's 4.8 per cent growth.

China will strive to achieve "reasonable" GDP growth in the second quarter, Li told thousands of government officials across China in an online conference.

Domestic air traffic has plummeted because of lockdowns in Shanghai and surrounding cities. Shanghai-based China Eastern said passenger numbers sank 90.7 per cent in April from a year earlier.

Australian Associated Press