A Fine Gael senator has told the Democratic Unionist Party to stop "whinging" about the Irish Government's post-Brexit border stance.

Neale Richmond hit out at the DUP and said instead of complaining, the party should be focusing on re-establishing the Northern Ireland Executive and Brexit discussions.

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

Mr Richmond was responding to DUP accusations that Taoiseach Leo Varadkar was politicking for domestic purposes when he said Ireland would not help Britain design an economic border for Brexiteers.

The DUP was left angry after Mr Varadkar said last week that the Irish Government does not want any sort of economic border on the island of Ireland after Brexit.

He said if Britain wants to put forward technological solutions, that is up to them, but the Government would not do that work for them.

Mr Richmond said the Irish Government and the EU "cannot be expected to provide all the solutions (in relation to Brexit), especially on areas like a proposed border which run contrary to the aims of the Irish Government or indeed the Good Friday Agreement".

He added: "Being a good friend requires one to be honest. In the Brexit debate, Ireland is the best friend the UK has and it is only right that the Taoiseach and Minister [for Foreign Affairs Simon] Coveney should point out when the UK negotiating side is lacking."

DUP deputy leader Nigel Dodds has strongly criticised what he described as Mr Varadkar's "intemperate, inconsistent and incoherent outbursts" on Brexit.

Mr Dodds said the Irish Government was sending mixed messages about Brexit and were taking things backwards.

He said what he called the "new regime" in Dublin appeared to have adopted a more hardline attitude to Brexit than that of the former taoiseach Enda Kenny and former minister for foreign affairs Charlie Flanagan.

Speaking in Waterford today, Mr Varadkar reiterated that Brexit was a British policy, not an Irish one.He added that he still hopes Brexit will not happen.

Meanwhile, the European Commission has declined to comment on the sharp differences between Dublin and London over Brexit, following the Taoiseach's remarks last Friday.

At the daily briefing to journalists in Brussels, commission spokesperson Mina Andreeva said the issue was part of the "ongoing negotiations" with the UK.

"Let the negotiators do their work. There is a working group on this so we will deal with this issue in a structured negotiation framework."

Earlier, a former special adviser to DUP leader Arlene Foster described as "extraordinary" Mr Varadkar's comments last week in relation to a border between Northern Ireland and the Republic of Ireland post-Brexit.

Speaking on RTÉ's Morning Ireland, Richard Bullick said, that traditionally, taoisigh have dealt with such issues with a measure of moderation and responsibility.

Mr Bullick said that private views are normally kept private, adding that it may be an issue of "somebody relatively recently into office that led them to say what they thought out loud, which isn't always the most desirable stance in politics".

He said both sides needed to work together and that this kind of language was not helpful.