Groups representing the UK's freight and logistics industries have warned of significant gaps in the British government's border preparations for the end of the Brexit transition period on 31 December.
Eight organisations, including the Road Haulage Association (RHA), are seeking an urgent meeting with ministers.
They have written to Cabinet Office Minister Michael Gove, who is overseeing the UK's Brexit preparations, to highlight fears the UK-EU supply chain "will be severely disrupted" from January if issues are not resolved.
The group wants a meeting with Mr Gove, Chancellor Rishi Sunak and Transport Secretary Grant Shapps to discuss areas including IT systems and physical border infrastructure.
The letter states: "As key participants in the supply chain who will be required to deliver a functional operating border for GB and EU traders next year, we have visibility of the current state of preparedness which as it stands has significant gaps.
"If these issues are not addressed disruption to UK business and the supply chain that we all rely so heavily on will be severely disrupted."
"The Covid pandemic has demonstrated to both government and the general public the importance of a free-flowing supply chain, and with transition occurring at the same time as a potential second Covid spike it is critical we ensure the supply chain is protected," the letter added.
"We are asking you to take seriously our concerns and listen to the detail during this roundtable so that we can collectively help Government manage through this enormous challenge with as little disruption as possible.
"Our aim, like yours, is to have a functional and effective border that allows goods to flow from January 1 2021."
Signatories to the letter also include Logistics UK, UK Warehousing Association, the Chartered Institute of Logistics and Transport, Cold Chain Federation, British Association of Removers, British International Freight Association and British Vehicle Rental and Leasing Association.
RHA chief executive Richard Burnett said: "There are a range of critical issues the Chancellor, Michael Gove and the Transport Secretary need to address ranging from the SmartFreight app and other untried and untested IT systems, to the lack of customs agents and clear processes for tackling the mountain of red tape traders will face.
"The Government's pace is simply too slow on this, and that's why we - the people who run the UK's supply chain - need an urgent meeting with those at the top of Government dealing with Brexit preparations."