Image copyright PACEMAKER Image caption Sir Jeffrey Donaldson urged Dublin to co-operate in finding a solution to the border question

"Megaphone diplomacy from Dublin" will not solve the problem of the Irish border once the UK leaves the EU, a Democratic Unionist Party MP has said. 

Sir Jeffrey Donaldson was responding to comments by the Irish prime minister about his opposition to any sort of economic border post-Brexit. 

Taoiseach (PM) Leo Varadkar has said he would not design a border for those who campaigned to leave the EU. 

Sir Jeffrey said non-cooperation from Dublin could result in a "hard border". 

"The Taoiseach needs to recognise that going back to the politics of the 70s and 80s in Anglo-Irish relations is not going to help anyone," he added. 

Sir Jeffrey was also responding to comments made on Monday by Fine Gael senator Neale Richmond, chair of the Irish Senate's Brexit committee. 

Mr Richmond said the taoiseach was right to criticise the UK's approach to Brexit negotiations and said subsequent DUP criticism of the Irish premier was "whinging". 

"The DUP's whinging doesn't hide their political impotence," he said. 

"They would be far better off seeking to influence their government partners in Westminster and working to get the executive back up and running to give Northern Ireland a strong voice." 

'One-sided'

Sir Jeffrey told the BBC the Brexit negotiations had only just begun and research was ongoing to ensure a "frictionless border". 

"You cannot design a solution until you have agreement on what that solution should be," he said. 

Image copyright Reuters Image caption The future of the border between Northern Ireland and the Republic of Ireland is a crucial Brexit issue

"Now if the Irish government is going to say they're not going to cooperate in designing a solution then of course... the UK will get on with designing a solution." 

Such a "one-sided approach" could lead to a so-called hard border which would impact on the Irish economy, he said. 

He also added that Mr Varadkar, who is due in Belfast later in the week, needed to be at the negotiating table. 

Image copyright PA Image caption Irish prime minister Leo Varadkar has said he will not design a border for Brexiteers

Sir Jeffrey also dismissed recent comments from Sinn Féin's Conor Murphy that the DUP privately acknowledged Brexit would be an "economic disaster" for Ireland. 

"Nonsense!  Conor Murphy just makes this stuff up as he goes along," he said. 

"The DUP believes privately what it says publicly.  We support Brexit and believe it will be good for the UK."