Johnson made the remarks during a visit to Belfast, Northern Ireland, on Monday, reports Xinhua news agency
Addressing concerns over possible checks on goods crossing the Irish Sea after Brexit, Johnson told reporters: "I cannot see any circumstances whatever in which there would be any need for checks on goods going from Northern Ireland to Great Britain.
"The only circumstances in which you could imagine the need for checks coming from Northern Ireland to Great Britain, as I have explained before, is if those goods were going on in to Ireland, and we had not secured which I hope and am confident we will a zero-tariff, zero-quota agreement with our friends and partners in the EU.
"There are plenty of protections for Northern Irish business, farmers and others."
Johnson's visit came three days after Northern Ireland's two major parties, the Democratic Unionist Party (DUP) and Sinn Fein, agreed on a draft deal to restore a power-sharing government, breaking a three-year political deadlock in the region.
Northern Ireland First Minister Arlene Foster of the DUP and Deputy First Minister Michelle O'Neill of Sinn Fein received Johnson at the door of Stormont, seat of the Northern Ireland Assembly.
Praising politic for their willingness to set aside differences, Johnson said that "now is the chance for the government and Executive to deliver for the people of Northern Ireland and to deliver on the priorities for the people".
In a statement prior to his visit, Johnson hailed the deal as "historic".
"This is an historic time for the people of Northern Ireland. After three years, Stormont is open for business again with an Executive who can now move forward with improving people's lives and delivering for all communities in Northern Ireland," the statement added.
( With inputs from IANS )