The Taoiseach has said that, while it is "always a possibility", it is extremely unlikely that one of the EU 27 countries could veto any proposal to grant the UK a longer extension to agree a Brexit deal.
Leo Varadkar said however that Ireland has stressed the need for solidarity, patience and understanding as some countries grow increasingly frustrated with how much time the process is taking.
Speaking on RTÉ's Countrywide programme, Mr Varadkar said that if one country was to veto an extension and as a result impose hardship on Ireland, as well as the Netherlands, Belgium and France "they wouldn't be forgiven for it".
He said any such country "would know they might find themselves on the other end of that particular veto power in the future".
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He said the European Council is working to agree Brexit on the basis of unanimity and it is rare that a veto is used.
Mr Varadkar said that it tends to operate by consensus and while that takes time and can be messy, it is why Europe works.
However, he acknowledged the increasing frustration in some countries in the EU further away from the UK such as Malta or Lithuania.
He said other countries are increasingly saying there are other things on the European agenda - including how to boost the economy, to deepen the single market, CAP reform and migration.
He said some member states see that Brexit is taking up an increasing amount of time and this is causing increasing frustration.
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Meanwhile, the Labour leader Brendan Howlin has said he will be "... very strongly advocating for the longest possible [Brexit] extension" for the UK.
Deputy Howlin said such a move was essential because he thought "... there is a real prospect of Britain thinking again [about leaving the EU] - that seems to be the consensus and movement".
The Labour leader described next Wednesday's EU leaders' summit as "critical" and said he would travel to Brussels and lobby the six Socialist EU Prime Ministers "... to ensure that view is heard".
He added: "Although we are all anxious for this ongoing [Brexit] agony to end, it's important that it's done in a way that is beneficial - as far as is possible - to the people of this country."