Prime Minister Boris Johnson has called for “symmetry and balance” to post-Brexit trade arrangements in Northern Ireland.

Unionists are fiercely opposed to the Northern Ireland Protocol and Mr Johnson was in “listening mode” as he held frank discussions with the DUP during a visit to Belfast and Co Fermanagh on Friday.

Mr Johnson said there had to be east-west as well as north-south consent after red tape on goods moving from Great Britain exposed fresh divisions between unionists and nationalists.

The Prime Minister said the protocol – which kept the Irish land border open but imposed extra paperwork on supplies from the rest of the UK – should guarantee the peace process and the 1998 Good Friday Agreement.

He said: “There has got to be a balance and symmetry in that.

“We want to ensure that the protocol upholds the wishes of both communities and has the consent of both.

“There has got to be east-west consent to what is going on, as well as north-south.

“We want to make sure that is built into that.”

Loyalists have expressed growing discontent at what they see as measures threatening Northern Ireland’s place in the UK.

The arrangements are designed to keep the region in the EU’s single market for goods to preserve frictionless business on the island.

Loyalist leaders wrote to the Prime Minister recently, withdrawing support for the Good Friday Agreement which largely ended decades of violence.

Consent was enshrined in the peace process.

The British Government has unilaterally extended until October some grace periods of light-touch regulation on goods arriving in Northern Ireland from Great Britain, which had been due to end at the end of this month.

The EU has threatened legal action in response.

Mr Johnson said: “We are taking some lawful, technical measures to build up confidence in the east-west operation as well.

“We think it is lawful, indeed we think it is right, in view of the impact on the peace process and the Good Friday Agreement and the need to have consent from both communities.”

The Prime Minister visited a mass vaccination centre with Stormont First Minister Arlene Foster in her Co Fermanagh constituency.

Afterwards the DUP leader described the conversation as frank.

She urged him to “stand up for Northern Ireland” and ditch the “intolerable” Protocol governing Irish Sea trade post-Brexit.

She said he had been in “listening mode” and “alive to the issues”.

The First Minister said: “Not a single unionist party in Northern Ireland supports this unworkable Protocol.

“Rather than protect the Belfast Agreement and its successor agreements, the Protocol has created societal division and economic harm.

“Whilst grace periods have been extended unilaterally, we need a permanent solution so business can plan and the integrity of the United Kingdom internal market can be restored.”

Mr Johnson was joined by the DUP leader and Stormont Health Minister Robin Swann at the converted Lakeland Forum leisure centre in Enniskillen.

Mrs Foster told the Prime Minister a local school in Fermanagh was unable to order trees from England due to red tape surrounding the transport of soil.

Her powersharing partner, Sinn Fein’s deputy First Minister Michelle O’Neill, refused to welcome the premier to Belfast on Friday in her Stormont role after a request for a political meeting with her and Sinn Fein leader Mary Lou McDonald was not accepted.

Ms O’Neill said: “Mary Lou McDonald and myself have a long-standing request to meet with the British Prime Minister to discuss a number of commitments which he and his Government have reneged on in the New Decade New Approach over this past year, and also his reckless and partisan approach to the Irish Protocol. He did not facilitate the meeting.

“I have no plans to meet with him today.”

Mr Johnson also visited RAF Aldergrove in Co Antrim on Friday.

Northern Ireland’s centenary programme marking the anniversary of the state’s foundation will champion young people of the future, the Prime Minister said.

It will also pay tribute to those who worked tirelessly to support the region during the pandemic, he added.

Plans for 2021 include a major business showcase in London, a £1 million Shared History Fund, an ambitious programme for young people, tree-planting projects, academic and historic events and an international church service for all denominations.