Northern Ireland businesses have reiterated a call for certainty over Brexit talks after reports that the UK could pass legislation bringing changes to the NI Protocol.
The Financial Times reported on Sunday that ministers were preparing a new bill which would overrule parts of the withdrawal agreement that was signed by the UK and the EU.
The NI Business Brexit Working Group said that while the Protocol - devised to avoid a hard border on the island of Ireland - was not perfect, it averted the "worst consequences of a chaotic non-negotiated outcome".
A spokesman said: "We have been working with the UK Government and the EU to remove frictions and make this protocol work as a starting point for the NI economy following the Brexit transition period.
"It would be greatly enhanced by a zero tariff, zero quota trade deal between the UK and the EU. Business continues to ask for the certainty that we need to prepare for the end of the transition in 16 weeks' time."
Frankie Devlin, from business advisers KPMG in Northern Ireland, urged businesses to focus on preparations for new customs, VAT and other trading requirements as set out in the NI Protocol.
"Clearly, a zero tariff, zero quota trade deal is what NI businesses require. The NI Protocol is an international agreement and it is the template that businesses have been given to work with; therefore now is the time for outstanding issues on its implementation to be agreed," he said.
And Stephen Kelly, chief executive of Manufacturing NI, also urged businesses not to be "triggered" by speculation over what the UK or EU might say next.
"The promise to NI firms that it can place its goods in the UK's internal market in an unfettered way needs to be delivered with legal certainty but that need not be done by putting at risk the unique arrangements and opportunities in the NI Protocol," he said.
"A disorderly end of this year is unwelcome and dangerous. For us it remains the case that a zero tariff, zero quota trade deal between the UK and the EU is in everyone's interests and all focus should be placed on achieving that aim.
"There has been lots of work done to make the Protocol work for businesses and consumers but business still seeks the detail and time to implement.
"We have neither just now meaning those who create and sustain jobs are being put in an invidious position. They deserve better."
This week a survey by Chartered Accountants Ireland warned that a lack of customs expertise on the island is holding back preparations.
News of a potential new stumbling block on the UK's road to negotiating a deal with the European Union before the end of the year sent the FTSE 100 soaring in London on Monday. The FTSE jumped by nearly 2.4% as it benefited from a weak pound.
It sent sterling tumbling by 0.9% against the dollar to 1.3159, and by 0.7% against the euro to 1.1136. The FTSE is populated by many exporters whose products become cheaper for foreign buyers when the pound falls. It had risen by 138.32 points to 5937.4 at the close of play on Monday.