China has hinted at maintaining its radical "zero-COVID" policy even after the upcoming twice-a-decade Communist Party congress, with the party's flagship newspaper, the People's Daily, running a commentary warning against complacency with anti-virus measures for three days in a row through Wednesday.

The paper claimed the strict policy to stem coronavirus infections, involving the imposition of lockdowns on cities when outbreaks occur, is still necessary given the spread of the highly contagious Omicron variant, the risks of mutations and a considerable number of elderly who have not completed vaccinations in China.

A man undergoes PCR testing in Beijing on Oct. 12, 2022. (Kyodo)

Once the stringent restrictions are relaxed, "a large number of severe cases and deaths will occur," causing a strain on the country's health care system, the commentary said. It dashed hopes that the party congress, to be convened on Sunday, could provide clues to a shift in the zero-COVID policy.

The newspaper referred to a recent surge in infection cases in Japan, saying its relaxed anti-virus measures have caused "serious consequences" with a stretched medical system.

Chinese Foreign Ministry spokeswoman Mao Ning defended the country's stringent anti-virus policy at a press conference in Beijing Wednesday, saying it is "the most cost-effective" measure. "Only by ensuring COVID security can we achieve steady economic growth," she said.

Under the stringent restrictions, people in China must undergo frequent COVID testing and present negative results on their smartphone app to enter public spaces. Movements are restricted in high-risk areas, and travelers from abroad are subject to a minimum quarantine period of seven days.

The Chinese mainland on Tuesday reported about 1,700 COVID cases, including asymptomatic carriers and no deaths, according to authorities.