Truck drivers will need a permit to enter Kent after the Brexit transition period ends, the government has said.
The announcement comes after a letter from cabinet minister Michael Gove warned that queues 7,000-trucks-long could clog up roads around the port of Dover and Channel Tunnel.
Speaking in the Commons, Mr Gove said the Kent Access Permit system would be enforced by police and ANPR cameras.
It is intended to ensure drivers have all the paperwork they need, he said.
Drivers of lorries weighing more than 7.5 tonnes will need to apply for the permits online and show that they have all the paperwork they need to ferry goods to Europe.
Mr Gove, the Chancellor of the Duchy of Lancaster, responsible for no-deal planning, wrote to logistics groups with the government's "reasonable worst-case scenario" planning for when the UK leaves the EU's single market and customs union rules on 1 January.
In that scenario, he said just half of big businesses and 20% of small businesses would be ready for the strict application of new EU requirements at the border.
"In those circumstances that could mean between only 30% and 60% of laden HGVs would arrive at the border with the necessary formalities completed for the goods on board," he told MPs.
"They'd therefore be turned back by the French border authorities, clogging the Dover to Calais crossing."
He said it could lead to delays of up to two days for drivers waiting to cross the Channel. Although he said those queues were likely to subside after businesses learned from seeing their cargo denied access to the continent.
The transition period is due to expire at the end of the year but only a quarter of businesses are "fully ready" for the post-Brexit arrangements, Mr Gove said.
Imports will also be disrupted in January, according to the letter sent to the freight industry by Mr Gove.
It also raises the prospect of a winter spike in Covid-19 leading to absences of port and border staff.
Labour's Shadow Chancellor of the Duchy of Lancaster, Rachel Reeves, said: "It is incredible that ministers are only now admitting to their plans to arrest British truckers for entering Kent without new travel passports.
With just over three months to go, how are businesses meant to prepare amid this Conservative carnival of incompetence?'"
The picture of chaos at the border might be familiar from a similar set of projections made for no-deal Brexit a year ago as part of what was known as Operation Yellowhammer.
The government says this is not a prediction but an illustration of what could be reasonably expected.
Moreover, Mr Gove told parliament on Wednesday the government was "absolutely determined to do everything that we can to secure a deal".
According to the Cabinet Office document, without a free trade deal and in its reasonable worst-case scenario, there may be "maximum queues of 7,000 port-bound trucks in Kent and associated maximum delays of up to two days".
"Both imports and exports could be disrupted to a similar extent," it says.
The EU is expected to impose full goods controls on the UK, stopping all freight without the correct documentation at the end of the transition period on 1 January.
The disruption is assumed to build in the first two weeks of January, and could last three months, or longer should France rigorously apply Schengen passport checks on hauliers at Dover and the Channel Tunnel.
The purpose of this stark communication is to try to get traders to act now to get ready for new border formalities that could help mitigate the disruption.
Mr Gove told the industry that this needs to happen irrespective of whether or not there is a deal in the UK-EU trade negotiations.
In response the freight industry says putting in place the measures needed to avoid border delays will be "a huge challenge for government and industry".
Logistics UK, representing road, rail, sea and air haulage firms says it is urging businesses to quickly install and understand the new processes they will need to use.
But firms need early access to both UK and EU systems so that they can conduct testing and training before 1 January, it says.
A recent meeting between the industry and government was described as a "washout", with insiders describing the relationship as "fraught" and hauliers fearful that they were being cast as the "fall guys" for delays and disruption likely in January.
There are further issues should there be no trade deal agreed. Hauliers would have to rely on special permits rationed by the Department for Transport, though a mutually beneficial deal here is possible.
But discussions on these issues await settlement of the impasse in negotiations on state aid and fisheries.
Industry sources have raised the possibility that the UK would have to sign up to EU rules limiting driver hours, in order to get access to EU roads.
And there is a specific new reference to France imposing strict passport checks at the "juxtaposed controls" currently designed to offer seamless travel across the Channel.
"There also remains a risk of continuing disruption caused by Schengen controls being applied rigorously at the juxtaposed controls at the Port of Dover and Eurotunnel," the document says.