DUP leader Jeffrey Donaldson has told party members its vote in the Northern Ireland council elections was a renewed mandate to continue its opposition to post-Brexit trade arrangements.
In a letter to the party's 122 councillors who were elected last week, the Lagan Valley MP said he would not ask nationalists to accept the kind of border infrastructure north-south that unionists are being asked to accept east-west, the so-called Irish Sea border.
"Last Thursday our mandate was renewed, and we were able to reaffirm our contract with the people to fully restore Northern Ireland's position in the United Kingdom," his letter states.
"Whilst the non-unionist commentators seek to pick holes in our mandate, I am heartened that we were able to increase our vote share from the NI Assembly election last year."
Mr Donaldson said the party is engaged in "a battle to build a Northern Ireland that we can hand on to our children and grandchildren."
He added: "The Northern Ireland Protocol placed a barrier between us and the rest of the United Kingdom which is offensive to us as unionists.
"Indeed, whilst nationalists seek to play down the impact of the Irish Sea border, we should all remember that Sinn Féin and SDLP politicians were in uproar at the very idea of any additional cameras being placed on the north-south border.
"Northern Ireland will struggle to move forward if republicans have so little respect for their unionist neighbours that they can't see the problem with the current protocol arrangements. I would never have expected nor asked my nationalist neighbours to accept the kind of infrastructure north-south that we are being asked to accept east-west.
"Alongside colleagues, I have consistently campaigned to ensure that the protocol is replaced by arrangements that restore our place within the United Kingdom. Those arrangements must be capable of commanding the support of unionists as well as nationalists."
The DUP leader once again said his party's decision to boycott power-sharing at Stormont in protest at the protocol had been vindicated although its successor, the Windsor Framework, still does not address all of its concerns.
"Consequently, more work is required by the UK Government if we are to secure the necessary conditions for a return to the Northern Ireland Executive," he added.
"We need to get this right in order to build a Northern Ireland that works for all.
"The people who voted last Thursday have renewed our mandate to finish the job and lay the necessary solid foundations for a return of local accountable government at Stormont."
Mr Donaldson also addressed the huge financial problems that will face any restored Stormont Executive following £800m (€920m) cuts imposed by the British Government in the absence of a devolved administration.
He again signalled a desire for the UK Treasury to help ease the pressures, but did not spell out any specific request.
The five main parties at Stormont have all said they believe an additional funding package of more than £1b (€1.15bn) will be required and the DUP is known to be involved in discussions with Northern Secretary Chris Heaton-Harris about a financial injection in the event of power sharing being restored.
"As an MP of 25 years, I also know the impact the current budget is having on our public services," his latter states,
"I have met with many of the people delivering vital services who are in receipt of redundancy notices but those spreading the notion that the restoration of Stormont will simply replenish every budget are doing an injustice to those public servants.
"The funding shortfall must be addressed for the long-term sustainability of both our public finances and public services, and this can only be done by the Treasury at Westminster."
Tánaiste and Minister for Foreign Affairs Micheál Martin and Mr Heaton-Harris have both welcomed the fact that the main parties are involved in discussions about the financial requirements needed for a restored Stormont Executive to function.
The DUP insists that will only happen after all of its concerns about the post-Brexit trade arrangements have been resolved.
