The British Prime Minister will attempt to calm fears over the Irish border when she begins a two-day trip to the North on Thursday.
Downing Street says Theresa May will insist there will be no return to a hard border in Ireland.
She will also reaffirm her commitment to the union - and reject calls for a border in the Irish sea.
The trip will see Mrs May meeting with business leaders and learning what it means to work, live and trade across the border.
Ministers are holding a special away day cabinet meeting in Derrynane in Kerry this morning to discuss Brexit contingency plans pic.twitter.com/MweajgGYWr
— Sean Defoe (@SeanDefoe) July 18, 2018
It comes as Irish ministers gathered in County Kerry to discuss Brexit contingency plans.
The Taoiseach Leo Varadkar said the meeting focused on Ireland's preparedness for a 'no-deal' Brexit.
Speaking outside the Cabinet meeting, the Tánaiste admitted negotiating with the British Government is frustrating as it keeps changing its position.
Simon Coveney said the Government is not making any preparations for a return to a hard border, because ministers do not believe it will happen.
"It is very frustrating for countries like Ireland many other countries - and certainly frustrating for the EU task force to be negotiating with a country that keeps changing its position.
"And when there is a new settled position published in a white paper, then there is a Parliamentary majority to support changes to that."
Mrs May narrowly avoided defeat on the UK Customs Bill on Monday by agreeing to a number of Brexiteer demands on its wording.
One of the amendments would make it illegal under UK law for Northern Ireland to form a separate customs territory to Britain.
The clause was passed without a vote.
