HONG Kong's Hutchinson Ports has announced a big expansion at Yantian, the company's first overseas terminal, at a time when the terminal is suffering unprecedented congestion brought on by extreme demand and a local outbreak of Covid-19.

Hutchision said it will develop a new terminal on the eastern side of the Yantian International Container Terminals (YICT) in Shenzhen. Yantian East International Container Terminals will be spread across 120 hectares and will feature 1,470 metre of quayside.

Yantian was Hutchison's first terminal to open outside of Hong Kong back in 1994. The port handled 13.34 million TEU last year.

Meanwhile, major shipping companies have warned clients of worsening congestion at the port, which has imposed stringent disinfection and quarantine measures since May 21 when the virus was discovered among port staff.

More than 40 container ships were anchored in open water outside the terminal, Refinitiv ship tracking data showed, according to Reuters.

Top international container lines said they would be skipping some port calls to Yantian to ease the pressure, while shipping sources added that some vessels may be re-routed to other destinations.

"The overall operation productivity at YICT has been adversely impacted, and we expect the current vessel berthing delays and port congestion situation will likely continue for at least a week," the world's number 2 line MSC said in a customer advisory.

The world's leading container line Maersk also warned in a recent letter that congestion and delays could last 12 days, longer than its previous expectation of 7-8 days.

Maersk estimated operations in the eastern area of the Yantian terminal, where larger vessels mainly berth, would remain at around 30 per cent of their normal level.

Other major shipping firms including COSCO Shipping , Hapag-Lloyd and ONE also alerted their customers to the growing delays and congestion and the possibility of not calling at Yantian.

Shipping companies and Chinese authorities have advised vessels to divert to nearby ports, including Shenzhen's west port and Guangzhou's Nansha port, which are operating normally despite sporadic cases of the coronavirus in the region.