An unprecedented surge in cargo imports from Asia has pushed container rates to the US and Europe to more than $4,000 per container.

The surge, which is driven by Covid-19 and is fuelling container markets, was not expected, and it is unclear how long it will last, according to a leading liner lobby.

"No one could have planned for the type of surges that are stressing the container transportation network, because the demand swings are unlike anything ever seen," said the Washington-based World Shipping Council (WSC).