AP Moller-Maersk A/S, one of the biggest shipping lines in the world, has stopped bookings to ship refrigerated containers into Shanghai as a strict Covid lockdown stalls the trucking of meat and seafood from the port into the city.

Containers are piling up at the port of Shanghai due to supply chain disruptions caused by the lockdown, Ocean Network Express said in an advisory to customers on Thursday. The port is running out of electric plug slots to keep refrigerated containers cool, while trucking remains limited and terminals are congested, Asia’s second-biggest container shipping line said.

That has prompted Maersk to stop all new deliveries of refrigerated goods and some hazardous cargoes into Shanghai until further notice, the company said on Thursday. The company is waiving charges for customers to change the destination of their frozen goods already sailing to Shanghai.

Shanghai’s sweeping restrictions aimed at ringfencing the spread of the omicron virus variant are now entering the third week, crippling supply chains and forcing ships to divert elsewhere. Meanwhile tensions between Shanghai’s residents and authorities are growing at the curbs on movement. Citizens have resorted to bartering items in exchange for fresh vegetables and milk.

China’s strict Covid Zero policy is even disrupting food supply chains as far south as Shenzhen. The e-commerce capital’s Shekou terminal has barred imports of frozen meat and seafood products, Hapag-Lloyd AG said on its website April 8. As shipping lines ask customers to divert shipments from Shanghai or Shekou to Yantian and Hong Kong, that’s threatening to worsen congestion in the southern ports, said Josh Brazil, director of supply chain data insights at project44.

“Hong Kong and Yantian have been battling their Covid restrictions for months, which has also been disruptive to manufacturing and trade,” said Brazil. “The Shanghai lockdown impacts South China shipping schedules.”