Hauliers reacted angrily after ministers warned of 7,000-truck-long queues in Kent if they fail to prepare for the end of the Brexit transition period.
They accused Michael Gove, the Chancellor of the Duchy of Lancaster who is responsible for no-deal planning, of attempting to "shift blame" for the possible impact of no trade deal being agreed with the EU.
In the document sent to logistics associations, which has been seen by the PA news agency, Mr Gove outlines a worst-case scenario in which between 30-50% of trucks crossing the Channel will not be ready for new regulations coming into force on January 1.
Rob Hollyman, director of Essex-based haulage firm Young's Transportation and Logistics, said this was "quite a clever statement" because it could lead people to blame "the idiot haulier".
He went on: "We can't possibly accommodate paperwork that we don't know we need, because we haven't been told.
"If the Government hasn't made clear what paperwork is required then it's not the 'idiot haulier' (to blame), it's the 'idiot Government', and it won't be 50% (of lorries not ready), it'll be nearly 100%."
Mr Hollyman said that if changes to customs rules are not properly communicated then "paperwork will be wrong" but "it sure as hell isn't down to the haulier".
He added: "No haulier in his right mind is going to wave the truck goodbye from his depot – £120,000 of equipment – not having done his research.
"(Ministers are) trying to shift blame away from the negotiators."
Richard Burnett, chief executive of the Road Haulage Association, warned that the UK does not have enough customs agents to support traders after the transition period ends.
He acknowledged that the industry is "nowhere near" being ready for changes to customs rules, but claimed "mixed messages" put out by the Government over whether a trade agreement will be reached with the EU have "created confusion".
He added: "We've got 71 working days to go from today. I don't think (ministers) understand the sheer scale of what needs to change. They certainly haven't listened."
In his letter, Mr Gove warns of possible two-day delays for cargo travelling to France in January.
He said: "Irrespective of the outcome of negotiations between the UK and EU, traders will face new customs controls and processes.
"Simply put, if traders, both in the UK and EU, have not completed the right paperwork, their goods will be stopped when entering the EU and disruption will occur.
"It is essential that traders act now and get ready for new formalities."
Mr Gove is due to outline the scenario work, which the Cabinet Office stressed is not a forecast, in the Commons on Wednesday.
It comes as the European Union's chief negotiator Michel Barnier holds further informal talks with his counterpart Lord Frost in London as efforts continue to strike a post-Brexit trade deal.
The transition period, which kept the UK aligned to the EU's single market and customs union rules to allow trade to flow smoothly after Brexit, expires at the end of the year unless both sides agree to an extension – something Boris Johnson has ruled out.
The Prime Minister has set a deadline of October 15 for an agreement to be reached, otherwise he has said he will simply walk away from the negotiating table.
A UK Government spokesman said: "With just 100 days to go until the end of the transition period it's vital that businesses prepare now for new rules that will come into force at the end of the year, so that they can hit the ground running on January 1 2021 and seize new opportunities.
"As a responsible Government we continue to make extensive preparations for a wide range of scenarios, including the reasonable worst case.
"This is not a forecast or prediction of what will happen but rather a stretching scenario."