ACTIVITY at the Port of Shanghai came to a halt on last week after US President Donald Trump's 125 per cent tariff on Chinese imports took effect, reports Caixin.

On April 7 and 8, nearly half the vessels docked at Shanghai's Yangshan and Waigaoqiao terminals were bound for the US, and racing against the clock.

Containers that missed the narrow window now sit idle in stacks along the docks. Many shippers are either pulling cargo back or scrambling for alternatives, according to an employee at shipping giant Cosco Shipping Holdings at Yangshan terminal.

Major shipping lines are drastically cutting back on transpacific routes. MSC, the world's largest shipping line, cancelled six voyages in April alone. Premier Alliance - a partnership of three major Asian shipping firms - postponed the launch of a new route planned for May.