The British Ports Association (BPA) has thrown its weight behind the UK government's agreement on a 'customs backstop' for Brexit.
The proposal would see the UK match EU trade tariffs temporarily in order to avoid a hard Irish border post-Brexit.
The arrangement gives terminals and freight operators a measure of short-term certainty, according to BPA chief executive Richard Ballantyne.
But he said: "It is now essential that government makes progress on our long-term customs and other border arrangements.
“There is still an urgent need for clarity on non-customs checks, which account for three quarters of border stoppages. These have the potential to cause huge disruption.
“We look forward to the passage of the EU Withdrawal Bill next week and hope that, whether various amendments are passed or defeated, we will have a clearer picture of what happens next."
The BPA is urging the government to speed up progress with the planned customs white paper to clarify the future relationship with the EU.
"We have made clear that, of the government’s two proposed policies, the customs partnership represents almost business as usual at the border for UK-EU trade, but whatever arrangement we choose it is vital there is time for ports to adapt to avoid disruption," Ballantyne said.