SHANGHAI: China is urging people to wear masks and gloves when opening mail, especially from abroad, after authorities suggested the first case of the Omicron coronavirus virus variant found in Beijing could have arrived via a package from Canada.

Authorities vowed to step up disinfection of overseas mail and are insisting postal staff handling it are fully vaccinated.

The precautions come less than three weeks before the capital opens the Winter Olympic Games and as several cities work to stamp out new outbreaks of coronavirus infections.

"Minimize purchases of overseas goods or receiving mail from abroad," state broadcaster CCTV said late on Monday in a social media post.

"Be sure to protect yourself during face-to-face handovers and wear masks and gloves; try to open the package outdoors."

Health officials said the person found infected with the Omicron variant opened a package from Canada that had been routed through the United States and Hong Kong and transmission via the package "could not be ruled out".

The case highlighted the importance of "personal defence", CCTV said.

Similar suggestions on how to handle parcels, not just those from overseas, were made by the National Health Commission on its official WeChat account and reposted by authorities in the cities of Shanghai and Nanjing.

China has been an outlier in asserting that COVID-19 can be transmitted via cold-chain imports such as frozen meat and fish, even though the World Health Organization has played down the risk, and has been pushing a narrative via state media that the virus existed abroad before it was discovered in late 2019 in the central city of Wuhan.

In recent weeks, China has been battling a resurgence in cases in several cities, some of them of the highly transmissible Omicron variant. On Tuesday, it reported 127 new local cases with confirmed symptoms.

The State Post Bureau issued a notice on Monday stating that international mail must be disinfected after reaching China, and staffers who process and deliver international mail must have received COVID-19 vaccinations and a booster.

China Post has also been reminding recipients of overseas mail to disinfect the contents "in a timely manner" with stickers pasted on parcels.