Boris Johnson’s failure to contact the Taoiseach since becoming Prime Minister has been branded “discourteous and offensive” by Sinn Fein.
In recent times incoming UK prime ministers have placed a call with their Irish counterpart on the first day of assuming office.
Five days after his appointment as Prime Minister, Mr Johnson had not had a conversation with Leo Varadkar.
It comes amid heightened tensions between the UK and Irish governments over the Brexit stand-off.
Government officials in London and Dublin have been in contact amid efforts to arrange a conversation between the leaders.
Arriving at Galway Races, Mr Varadkar said there were no plans for talks with Mr Johnson on Monday.
A spokesman for the Taoiseach later said he hoped the men would speak in the “near future”.
Sinn Fein vice president Michelle O’Neill accused Mr Johnson of “snubbing” Mr Varadkar.
It is concerning that British PM Boris Johnson has failed to make contact with Irish Gov since coming into office.
This lack of communication is highly offensive given the disastrous impact that Brexit will have for Ireland.
We raised this issue with British SOS Julian Smith. pic.twitter.com/yQCZjhNveH
— Michelle O’Neill (@moneillsf) July 29, 2019
She raised the matter during a meeting with Northern Ireland’s new secretary of state Julian Smith at Stormont on Monday.
“I would judge that it is highly discourteous that the new Prime Minister Boris Johnson is not engaging with the Taoiseach,” she said.
“That is highly offensive given the disastrous impact of Brexit on the island of Ireland.”
Mrs O’Neill said Mr Smith did not offer an explanation as to why there had been no contact between the prime ministers.
She said it was not up to her who made the first move in initiating a conversation.
“Whoever phones who first, the issue that needs to be discussed are the implications, the catastrophic implications for the island of Ireland so I think whenever the Taoiseach and Boris Johnson speak at some stage I think the message will be very, very clear from An Taoiseach – which will be around Brexit, the need to protect the Good Friday Agreement, it will be around the fact the withdrawal agreement needs to be adhered to and agreed because this is what the British government negotiated themselves a short time ago,” she said.
Mrs O’Neill added: “British-Irish relations are very important, that does strike right to the heart of the Good Friday Agreement, but the jeopardy that the British government want to bring to our people on this island cannot be understated – it is huge, it’s going to impact for generations to come.”
Mrs O’Neill said the rhetoric from Downing Street and the “right-wing cabinet” did not suggest there was going to be a Brexit deal achieved by the October deadline.
She said she did not know Mr Johnson’s motivation in threatening to leave the EU without an agreement.
“Is he electioneering, is he bluffing, is he trying to strengthen his hand in a negotiation? I don’t know is the answer,” she said.
“What I am fixated on, what I am concerned about is what it means for the people here.”
The Sinn Fein Assembly member added: “The language we have heard from Downing Street and the cabinet team over the course of the weekend has been very frightening for people on the ground.”
Mrs O’Neill rejected the suggestion the Government might move to legislate to introduce direct rule in Northern Ireland ahead of the October 31 Brexit deadline, if devolution has not be restored by then.
“Direct rule is not acceptable, we cannot go backwards, we can only go forwards,” she said.
The republican leader said she told Mr Smith he could not be a “bystander” in negotiations to restore powersharing, insisting “rights-based issues” at the heart of the impasse, such as Irish language protections, remained unresolved.

After holding talks with Mr Smith at Stormont, DUP MP Gavin Robinson declined to be drawn on the lack of a phone call between Mr Johnson and Mr Varadkar.
“I don’t think we need to get involved in who is phoning who; why they haven’t phoned yet,” he said.
“Matters between the British Government and the European Union will continue, they will engage in discussions and I have no doubt the Prime Minister and Taoiseach will discuss as well.”
Asked if he viewed it as a snub, Mr Robinson said: “I think we have a new administration. You can see the Prime Minister is travelling right across the United Kingdom, visiting Scotland today, going to be in Northern Ireland this week announcing investment for every part of the United Kingdom. That’s good news, that’s what he’s going to do.
“He will engage, no doubt, with all of the European Union member states, including the Irish Republic.”

Ulster Unionist leader Robin Swann also downplayed the issue.
“Boris Johnson has just taken over as prime minister of the world’s fifth largest economy, he’s his own party machinations to deal with on how he goes forward, he’s in Scotland at the minute I’m sure he’ll make contact with Leo at some point and see where we are actually going with this process,” he said.
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