Businesspeople have said they are aiming to ensure Northern Ireland's interests are not overlooked as the UK sets its sights on trade agreements with the EU and US.
It came after weekend reports that the UK was seeking ways of getting around the NI protocol in the EU Withdrawal Agreement.
Aodhan Connolly, director of the NI Retail Consortium, said he believed there was "a mixture of bluster and poker-playing" from the UK Government.
"The uncertainty doesn't help Northern Ireland business and it's the opposite of what we need."
The Sunday Times reported that officials were seeking to evade Irish Sea checks on goods passing from Great Britain to Northern Ireland. In response, a UK Government spokesman said the UK would comply with its obligations under the agreement.
During a visit to Northern Ireland yesterday, the new Northern Ireland Secretary Brandon Lewis said: "We always said there will not be a border down the Irish Sea, there'll be unfettered access for business."
Mr Connolly said NI business needed to continue to speak up as the UK's focus moves in due course to negotiating trade deals with the EU and US.
"We in Northern Ireland are part of a bigger game. The UK's focus will now be on trading agreements with EU and US.
"The job of the business community is to make sure needs are not forgotten while the sooner we have government in (the Irish Republic) the better."
Seamus Leheny, regional manager of the Freight Transport Association in NI, said: "We can only deal in facts so when we read the Withdrawal Agreement, that is what we must work towards.
"This means we have to prepare for new formalities. In some aspect it's correct to say we won't have checks on Great Britain to Northern Ireland trade because checks are only the result of whatever formalities are required, which will all be dependent on the type of trade agreement the UK and EU agree on.
"Checks will only ever be required to enforce compliance, which we hope will not be necessary.
"Rather than try and open up the negotiated Withdrawal Agreement, we would hope that the UK and EU agree a close free-trade agreement that means we face minimum formalities and close alignment, thereby making the need for such checks and associated bureaucracy redundant."
Mr Leheny added: "The clock is against us on this, our members would prefer clarity and assurances so that we as an industry can prepare accordingly, something we can't fully do yet."
The House of Lords EU Committee visits Belfast today as part of its inquiry into the Protocol. It will hear from business leaders including Graham Keddie, managing director of Belfast International Airport, and Les Stracey of Stena Line.