The government must clarify plans around new customs processes as firms remain in the dark about crucial aspects of their operation, says the British Chambers of Commerce (BCC).
The first phase of the UK's Border Target Operating Model began on 31 January, with imports of plant and animal products now requiring export health certificates.
It is the first time for decades that EU firms will have to provide this documentation for goods they are sending to Great Britain. The BCC says it is unclear how prepared they are for the change.
The business group says there is more concern over a lack of clarity around physical checks of consignments, due to start in April.
Government figures show the UK imports just under 30% of all the food it consumes from the EU.
William Bain, Head of Trade Policy at the BCC, said:
'The government is finally implementing major changes to Great Britain's inbound border controls and customs checks stemming from Brexit, but there are still unanswered questions around its plans.
'Especially, as businesses are already facing a tough start to the year, with container shipping prices quadrupling as the Red Sea disruption continues.
'The initial changes … should not cause many noticeable hold ups for inbound goods, although EU firms will be facing new charges to get export health certificates and will need to find vets to sign them.
'The bigger issue is physical checks on a proportion of these imports, which are due to start in April.'
Internet link: BCC website