The prospect of an invasion of Ukraine has become an expectation among world leaders rather than a possibility, Simon Coveney says.
He says the outlook for avoiding war in the region is "pretty bleak" at the moment.
The Foreign Affairs Minister has been meeting with other international ministers and officials at the Munich Security Conference this weekend, amid escalating tensions in eastern Europe.
Ukraine's President yesterday called on nations to find a diplomatic solution to deescalate the crisis.
While Russia has continued to deny that it plans to invade Ukraine, US President Joe Biden has claimed Vladimir Putin has made the decision and an attack could happen within days.
Minister Coveney says the build-up of troops on the border between Russia and its neighbour is increasingly concerning.
He told Newstalk's On The Record: "The view of virtually everybody I've met is that some form of invasion of Ukraine is now the expectation rather than a possibility.
"While there are clear commitments to continue to pursue diplomatic solutions and also to put a very strong deterrent in place to prevent Russia from making that decision... the expectation and intelligence that informs that expectation is giving a very negative outlook of what we're likely to see in the next few days."
He said there's still an obligation on the international community to try to defuse tensions, and that they need to call on Russia to make moves to deescalate the situation on the ground.
However, he said the opposite is now happening - pointing to Russian troops now staying in Belarus 'indefinitely' despite having only meant to be there for temporary exercises.
Minister Coveney says the images in Russian media of Russian-backed separatists in eastern Ukraine evacuating people across the border "is viewed as trying to create, through false information, the justification for military action".
He does believe there is still the potential for diplomatic intervention and de-escalation.
However, he said: "I think it's important I'm honest with the public on this - there is a real sense of foreboding that things are moving in the wrong direction.
"The response to that, I think, has to be for us to continue to try."
Minister Coveney said they'll continue to look for diplomatic ways of avoiding war, but the "outlook at the moment is pretty bleak".
He said it's not yet clear whether an invasion would be an "intensification" of military conflict in eastern Ukraine, or an "all-out invasion" of the country and its capital Kyiv.
Russian officials - including the Russian ambassador to Ireland - have insisted no invasion is planned, and have blamed the West for inflaming tensions.
However, Minister Coveney suggested such claims are "not credible any longer", adding: "I'm not sure it was ever credible, to be honest."
He said an invasion would "fundamentally change" the relationship between Russia and the rest of Europe for some time to come.