Maersk said bottlenecks in Shanghai are starting to ease with warehouse operations partially operating again but the shipping giant noted that trucking remains "very limited" in the city as China continues to harden its strict "zero-Covid" policy that began on March 28.

The shipping line told its customers that it is still closely monitoring the Covid-19 situation in Shanghai as supply chain disruptions grow from the almost-month-long lockdown in the major shipping and air cargo hub.

"Currently, all terminals in Shanghai are operating relatively normally, with all gate in and out activities and vessel- and terminal handling operations performing well. After a period of closure, warehouses in the area are partially operating again. However, trucking availability is currently limited," Maersk said in an update related to Shanghai on April 22.

The shipping line noted that it is implementing rerouting for some cargo and also expanding its barge and rail operations to minimize the impact of the ongoing disruptions in Shanghai.

From a full lockdown, Shanghai has transitioned into a tiered system in which neighborhoods are divided into three categories based on the risk of transmission with those in the first category facing the strictest Covid controls and being the main target of the new heightened measures.

Meanwhile, companies in Shanghai are restarting operations through a "closed-loop system" after submitting plans to authorities on how to halt the spread of the coronavirus.

"We are working hard to help re-route cargo where possible to mitigate delays and avoid bottlenecking and ensure that impacts to your supply chain are as minimal as possible," Maersk said.

"At the same time, we are looking closely at how we can adjust both our barge and rail capacity to help offset landside issues, given the described limitations."

The latest outbreak, driven by the omicron variant has counted hundreds of thousands of cases in Shanghai but fewer than 100 deaths since the outbreak began nearly two months ago.

On Saturday, Shanghai reported 39 new COVID-19 deaths, raising the death toll to 4,725.

A week earlier, Maersk announced that it is halting reefer bookings to the major cargo and shipping hub starting April 14 until further notice due to the impact of the lockdown as it cited both the reefer and dangerous cargo yard congestion in Shanghai terminals.