On the second of a two-day visit to Northern Ireland on Friday, when May will meet with businesses on the border in Fermanagh, she will urge the European Union to accept her proposals for a free trade area on goods.
On Thursday, the UK's new Brexit secretary Dominic Raab had his first meeting with the EU's chief negotiator in Brussels.
However, Mrs May's white paper would be the focus of later talks, during the "transition period", with the withdrawal agreement and Irish border the EU's priority on Friday.
One of several amendments passed by the British parliament this week accepted Brexit campaigners' demands for a legal guarantee that there would be no post-Brexit customs border between Northern Ireland and the rest of the United Kingdom.
She will add: "Not simply to fall back on to previous positions which have already been proven unworkable".
"The way in which global trade and political negotiations and agreements happen is that governments negotiate on behalf of their countries and then they go back once an agreement is made to look for support and ratification", he said.More news: Trump thanks Novartis, Pfizer for not raising drug prices
The sticking point in the EU-UK negotiations, so far, has been around the proposed customs backstop - an arrangement that will apply to the Irish border after Brexit, if a wider deal or technological solution can not keep it as frictionless as it is now.
She is expected to say the European Union needs to "evolve its position in kind", adding that "on that basis, I look forward to resuming constructive discussions".
"From the start of the negotiations, the UK Government has put Northern Ireland's unique circumstances at the heart of our negotiations", a statement said.
"For our part, we want to see a sensible exit from the European Union which works for Northern Ireland, the United Kingdom and our nearest neighbours in the Republic of Ireland".
"Our job is not to deal with Brexit in theory, but to make a success of it in practice for all of our people".
He also added that: "The most important thing is we all work really hard to avoid a no-deal Brexit".More news: DRAGON BALL SUPER: BROLY Trailer Sets Up a Huge Fight
Northern Ireland has been without a functioning devolved government for 18 months due to a bitter fallout between the two biggest parties - Sinn Fein and the Conservatives' "confidence and supply" partners at Westminster, the Democratic Unionists.
She will also speak to young people to hear their views on Northern Ireland's future, for them and generations to come.
Mrs May has also been meeting the five main Stormont party leaders during her visit to Northern Ireland to discuss Brexit and the political deadlock at Stormont.
She will then give her speech on Brexit at the Waterfront Hall in Belfast.
The prime minister said a seamless border is "the foundation stone" of the peace agreement that ended decades of violence between Protestants and Catholics as well as between Britain and those wanting to unite Ireland with Northern Ireland.More news: Spain: Judge drops extradition bids for 6 Catalan fugitives