Stricter control and prevention measures have been introduced to fight COVID-19 in Shenzhen, Guangdong province, as the city remains at high risk of community transmission, a senior official said on Monday.

Metro and bus services have been suspended and people working for the government and enterprises have been told to work from home to help curb the spread of the novel coronavirus in the city, Huang Qiang, deputy secretary-general of Shenzhen's city government, said at a news conference on Monday.

A number of manufacturing plants in Shenzhen, including those making iPhones, have halted production, after the southern megacity moved to take strict anti-epidemic measures in order to control a new wave of Omicron cases.

As the city stepped up its epidemic control measures and ordered the temporary suspension of production, industry experts said the situation could add more uncertainty to disrupted global supply chain.

Ocean carriers are scrambling to adjust their networks as the Chinese city of Shenzhen begins a week-long lockdown.

According to a notice issued by the Shenzhen Covid-19 Prevention and Control Command Office, the tech-city’s circa-17m residents must stay at home until Sunday – apart from going out for three rounds of testing – following which, “adjustments will be made according to the new situation”.

There are also fears that China’s strategy of Covid elimination will be extended to other mainland cities, despite the “relatively mild” symptoms of the Omicron variant.

But it is certainly “another spanner in the works” for supply chains hitherto beginning to show signs of returning to some form of normalisation. In fact, prior to this new disruption, carriers such as Maersk and Hapag-Lloyd were predicting that schedule reliability (and rates) would improve in the second half of the year.

The disruption is also likely to halt the hitherto gradual erosion of spot and short-term freight rates on the Asia-Europe tradelane, with rates across all Chinese export lanes reflecting pent-up demand increases for shipments.