UK exports to the EU slumped by 68% in January amid Brexit border chaos, hauliers have said.
The government did not confirm the data, insisting disruption at the border had been minimal since the end of the transition period.
But since the start of the year, businesses and hauliers have had to adapt to new trading arrangements, including new systems for companies and officials in the British province of Northern Ireland.
Firms have struggled with new customs declarations and health certificates as the coronavirus pandemic also hits firms.
International members at the Road Haulage Association (RHA) reported a 68% fall in exports in January, the group said on Twitter.
"I find it deeply frustrating and annoying that ministers have chosen not to listen to the industry and experts," RHA Chief Executive Richard Burnett told The Observer newspaper.
He said as many as 75% of vehicles that had arrived in the UK from the EU were going back empty because there were no goods to return with them due to hold ups on the UK side.
And he blasted Michael Gove, saying what little contact they had had with the minister in charge of Brexit had been a "waste of time."
He said: "Pretty much every time we have written over the last six months he has not responded in writing. He tends to get officials to start working on things.
"But the responses are a complete waste of time"
The government said it engages with the sector and does "not recognise the figure provided on exports."
"Thanks to the hard work of hauliers and traders to prepare for change, disruption at the border has so far been minimal and freight movements are now close to normal levels, despite the COVID-19 pandemic," it said in a statement.
