Varadkar has not been in touch with May in six weeks
Taoiseach Leo Varadkar and British Prime Minister Theresa May have had no contact in six weeks despite impasses in Brexit and the re-establishment of the Northern Ireland Assembly.
In a further sign of deteriorating Anglo-Irish relations, Mr Varadkar admitted neither side have sought to touch base since March.
"There has not been a formal phone call or meeting between the two of us in about six weeks, nor has there been a request for one on either direction," he said.
A meeting is under consideration next week on the fringes of an EU conference both leaders will attend in Bulgaria.
In the Dáil, Mr Varadkar sought to play down the significance of the gap in contact.
"Prime Minister May and I have each others' mobile phone numbers and it is possible for us to contact each other whenever we need to but currently the focus is on negotiations in Brussels and the various cabinet meetings taking place in the UK to determine their position on the customs union or the customs union partnership and how that might evolve," he said.
Fianna Fáil leader Micheál Martin said he believed a "combination of chaos and disinterest in London" was to blame.
"I do not think that the Taoiseach will find a period in the last 25 years when a Taoiseach and a prime minister went for so long without talking, especially during such a crisis as that of the suspension of Northern institutions or of Brexit," he said.
Meanwhile, Tánaiste and Foreign Affairs Minister Simon Coveney and Minister for Europe Helen McEntee held the Future of Europe Dialogue ahead of Europe Day.
The event was a culmination of citizens' events across the State led by Ms McEntee on the topic of Europe.
In his address, Mr Coveney pointed to the internal threats facing the EU; and Ireland's place within the EU, without Britain. He said Europe was "facing the rise of populism, and strident political voices - both from inside and outside".
Notwithstanding Brexit, Mr Coveney said while a member state of the EU has decided to leave, "others are getting ready to join".
He said part of the results from speaking to citizens was that Irish people are attached to our traditional policy of military "neutrality", "on the one hand, and a recognition, on the other, that there are new, asymmetric threats that we cannot cope with alone".
Co-operation under the EU military body PESCO (Permanent Structured Co-operation) would "make us safer in the face of asymmetric threats such as terrorism, extremism and cyber-attacks", he said.
"Ireland will play its part, in a way that reflects the wishes of our citizens," said Ms McEntee.
In the UK, confusion and paralysis continues to reign over the Border after Brexit.
Anti-Brexit campaigners have rubbished David Trimble's suggestion that mobile phone technology and sat nav tracking could solve the Irish Border question as somewhere between "magical and economically dangerous".
The former first minister has thrown his weight behind the so-called 'Max Fac' option for resolving the Border problem that has dogged Brexit negotiations.
This 'smart border' proposal argues that technology such as mobile phone and GPS technology can track lorries carrying goods, together with the computer-based customs clearing.
These solutions have already been fully ruled out by Ireland and the EU.