Irish goods entering the Northern Ireland market will not face tariffs in a no deal Brexit.
However, Irish products entering the rest of the UK would face high tariffs on a range of food products.
The details are contained in a new no deal Brexit plan published by the government.
It says the plan recognises the unique circumstances of Northern Ireland.
It is possible that while Irish products would enter Northern Ireland tariff free, products moving in the other direction would face tariffs.
The government said it recognises that Northern Ireland’s businesses and farmers will have concerns about the impact that the government’s approach will have on their competitiveness.
It stated: “These are the only steps the UK government can unilaterally take to deliver on our absolute commitment to avoid a hard border in the event of no deal.”
It added that there will be no checks or controls on goods moving from Ireland to NI.
It is still not clear what the Irish government will do on its side of the border if Britain leaves the EU without a deal.
The prime minister lost a second vote on her withdrawal deal in Parliament by 149 votes on Tuesday evening.
Those voting against the deal included the 10 Democratic Unionist Party (DUP) MPs.
Opposition to the government’s plan focused on the backstop, the insurance policy to avoid a hard Irish border after Brexit in the event of a wider trade deal not being reached.
The DUP will vote against a motion in Parliament that would rule out the UK leaving the EU with no deal.