According to the business organization, a poll of more than 200 companies showed that three quarters of them said they are experiencing delays of up to two weeks when importing supplies or exporting products to the European bloc.
More than a third have lost revenue, while one in five complained that they had lost potential business, Make UK said.
The United Kingdom left the EU on 31 January 2020, triggering an 11-month transition period that gave both London and Brussels time to conclude a range of agreements, including a wide-ranging free trade deal.
After months of negotiations, both parties reached a trade deal on 24 December, avoiding the prospect of a no-deal Brexit with just one week to spare.
More than two months into the divorce, both sides have repeatedly clashed on issues going from the so-called Northern Ireland Protocol, which was inked to avoid hard border with Ireland and customs and veterinary regulations, to the COVID-19 vaccines.
"Government should look to quickly get back around the table with our EU partners to find a way to mitigate against ongoing delays at the border and iron out different interpretations of the rules for movement of goods in separate member states," Stephen Phipson, chief executive of Make UK, said, as quoted by The Financial Time newspaper.
According to the specialized news outlet, the UK is expected to unveil next week a new scheme to help smaller businesses cope with the burden of Brexit red tape, and has pledged to train thousands of new customs agents.
