Sinn Féin's Michelle O'Neill said Mrs May will "hear the dismay and alarm that exists here"
Theresa May has arrived in Fermanagh at the start of a two-day visit to Northern Ireland, travelling to the border for the first time since she became prime minister.
Her visit to the Irish border area comes amid the ongoing political turmoil over her government's Brexit plans.
Downing Street said the British Prime Minister is meeting with local businesses to hear their views on "what working, living and trading across the border means to them".
She is visiting the area with Northern Secretary Karen Bradley.
Mrs May is also meeting with political parties as part of efforts to restore the devolved government at Stormont.
Northern Ireland has been without an Executive since early 2017.
Ahead of the prime minister's visit, Sinn Féin leader in the North Michelle O'Neill said the British leader had 'finally' agreed to visit a border constituency two years after the Brexit referendum.
She said: “She will hear the dismay and alarm that exists here in this community.
“Sinn Féin will meet with Theresa May on Friday and we will set out our serious concerns in regards to her government’s chaos and their blatant disregard for the citizens of the north."
Meanwhile, DUP leader Arlene Foster said Mrs May was coming to hear "first hand of the issues around the border - around the opportunities, and indeed some of the challenges that there are."
Speaking before her trip, Mrs May again reaffirmed that there will be no hard border on the island of Ireland.
She said: "Daily journeys will continue to be seamless and there will be no checks or infrastructure at the border to get in the way of this.
"I’ve also been clear we will not accept the imposition of any border down the Irish Sea and we will preserve the integrity of the UK’s internal market and Northern Ireland’s place within it."
Tomorrow, Mrs May will deliver a speech in Belfast outlining details of the 'white paper' proposals on the future relationship with the EU.
Mrs May's visit comes after her government managed to narrowly win a number of significant Brexit votes in the House of Commons.
However, political uncertainty at Westminster continues following the recent resignations of Brexit secretary David Davis and foreign secretary Boris Johnson over Mrs May's Brexit plans.
Today, the UK's new Brexit secretary Dominic Raab met the EU's chief negotiator Michel Barnier as the latest round of talks got under way in Brussels.
Mr Barnier warned that the agreement of an "all-weather insurance policy" for the Irish border remains a "matter of urgency" in negotiations.