A 12-month grace period and urgent financial aid is needed to iron out problems with the post-Brexit Irish Sea trade border, hauliers said.
It is quicker to send goods between Northern Ireland and Spain than from the rest of the UK, they added.
The industry has warned that the UK government must intervene with extra cash before jobs are lost at freight companies.
The end of the Brexit transition period has produced deep-seated structural problems which will not be quick to resolve, the Road Haulage Association (RHA) said.
Volumes of trade from the rest of the UK to Northern Ireland has fallen sharply and many suppliers are avoiding the route. Dozens of lorries have been left sitting in yards in Britain.
RHA chief executive Richard Burnett said: “This is a financial precipice haemorrhaging money.
“There needs to be financial intervention immediately.”
12 hours
New customs declarations were taking 12 hours, when hauliers were promised it would take 30 seconds.
Some drivers who can depart Irish Sea ports are having to produce 300 pages of paperwork, the transport firms added.
Dozens of staff helping with red tape are off sick because of coronavirus, the industry said.
Some freight companies are seeing a third of business disappearing, Mr Burnett added.
He warned: “There are going to be jobs lost, that is the bottom line here.”
He said issues encountered since the end of the transition period were not teething problems.
“These are significant structural issues. Government needs to intervene quickly with financial support to address this issue.”
I know we are insignificant to you in Great Britain
Peter Summerton, managing director of haulage company McCulla Ireland, said these were not temporary problems.
He asked: “What are we trying to do? Break the Northern Ireland economy by breaking Northern Ireland hauliers?
“The trade imbalance cannot be maintained, it is not unfettered access.
“We can move product from Northern Ireland to Spain faster than we can move product from England to Northern Ireland.”
Another haulier, Paul Lutton, addressed a virtual meeting organised by the UK Labour Party on Wednesday.
He said: “I know we are insignificant to you in Great Britain, we are only a small town but we want to be part of Great Britain.
“You have said you can be, you are not helping us out.
“I am flabbergasted.”
The delays are caused by the post-Brexit Northern Ireland protocol, which means the region must follow the EU’s customs rules to prevent a hard Irish border.
