Boris Johnson has suggested an Irish unity referendum is a 'very, very long time' away.
Debate about a border poll has intensified in recent years, with several groups in the Republic calling for officials to start planning for a vote in the future.
Former Taoiseach Bertie Ahern believes a vote is 'inevitable' in the next ten years - and thinks it should be held in 2028 to coincide with the 30th anniversary of the Good Friday Agreement.
However, the British Prime Minister doesn't envisage such a poll for "a very, very long time to come".
Speaking to BBC Northern Ireland's Spotlight programme, Mr Johnson said he'd rather people in the UK think collectively about what they can do together than splitting themselves apart.
Mr Johnson also insisted he'd remove what he described as 'unnecessary and ludicrous' between Northern Ireland and Great Britain.
He said work was underway to 'sandpaper' the post-Brexit Northern Ireland protocol "into shape".
BBC also reports that Taoiseach Micheál Martin suggested calling for an early border poll would be "very explosive and divisive".
Responding to Boris Johnson's comments, Mr Martin this morning said the Irish Government's position is clear.
He said: “We want to see the fulfilment of the potential of the Good Friday Agreement.
“I’m conscious there are other elections going on in the UK at the moment, and maybe there was a context for those comments. But I’m very clear in terms of the need to fulfil all aspects of the Good Friday Agreement."
He pointed to the Government's €500 million shared island fund, which aims to support collaborative North/South projects such as the Ulster Canal.
Meanwhile, the Taoiseach said the focus now should be on reducing tensions in the North over issues such as the protocol.
He said: “I’m happy to see the EU and UK are now engaging in a serious way in relation to resolving issues that have arisen in terms of the operation of the protocol. There is still some progress to go."
