Business leader Sinead McLaughlin visited 10 Downing Street on Wednesday and told Theresa May how difficult Brexit will be for local businesses.
The Chamber of Commerce chief executive was a guest at a private reception on International Women's Day.
Ms. McLaughlin told the United Kingdom leader Brexit will drastically impinge on the border region.
She said: "Attending the event at 10 Downing Street gave me the opportunity to speak directly, one-to-one, with the Prime Minister.
"I explained to Theresa May the economic difficulties faced by businesses in the North West and about the specific challenges presented by Brexit.
"These include the practicalities around the border and the potential impacts of tariff differentials in the two jurisdictions."
The Londonderry Chamber of Commerce boss added: "I asked the Prime Minister to become directly involved in the current negotiations at Stormont so that the restoration of the assembly can take place in the very near future."