Business groups in Northern Ireland say they “desperately need” more detail on how the new Irish Sea trade border will work.
It is due to begin operating in January when the Brexit transition period ends.
It will involve new checks and controls on goods entering NI from GB, but the precise details are still to be negotiated by the UK and EU.
The UK government has proposed a light touch approach with no new customs infrastructure.
The Northern Ireland Business Brexit Working Group (NIBBWG) has responded to those proposals.
“While the ambitions of the UK government are laudable, there is a need for technical detail to allow business to prepare for the changes that will come into force on 1 January 2021,” the group said.
It says details are needed on how trusted trader schemes will work and how goods will flow both ways across the Irish Sea.
The group is also calling for greater engagement from the UK government.
“Over the past few weeks, as a group, we have met with a delegation from the EU Task Force as well as representatives from the main political parties in Northern Ireland and that has been extremely useful,” said Aodhán Connolly of the Northern Ireland Retail Consortium.
“But, given the impending ending of the transition period in six months and the level of preparations that will need to be made, we must be able to voice our concerns with the Westminster government and our political leaders in the executive.”
It comes as Stormont officials warn that they have less than three weeks to finalise plans for facilities to check goods.
Plans for extended facilities at ports and airports must be approved by the European Commission.
Northern Ireland’s Chief Vet Robert Huey said in order for the approvals to be in place by the end of the transition period, the application would need to be completed by 23 June 2020.
Stormont’s agriculture and environment committee was told that detailed planning work had only been able to start on 27 May, the day after the UK government published its view on how the Northern Ireland protocol would work.
Meetings have now been held with Larne, Belfast, Warrenpoint, Foyle and the two main airports with officials working seven days a week on the plans