While the typhoon led to the temporary closure of both ports, the impact has been longer lasting, creating queues of ships waiting to load and unload, which is having a knock-on effect on sailing schedules that are already disrupted, reports IHS Media.
Maersk said the delays at Shanghai, the world's busiest container port, are likely to last at least another week.
'Shanghai is suffering port congestion clearing the backlog caused by Typhoon In-fa,' Maersk said. 'For Maersk, we see the waiting time is between two to four days in the Waigaoqiao and Yangshan areas. We expect the situation will recover in a week's time or perhaps longer.'
Yangshan is Shanghai's main port area in Hangzhou Bay about 80 miles from the city centre, while Waigaoqiao is in Shanghai's Pudong district where APM Terminals operates Shanghai East Container Terminal in a joint venture with Shanghai International Port Group.