A faster process is needed for countries to become members of the European Union, the Taoiseach has said.
Micheál Martin declared that Ireland will push for the "shortest possible timeframe" for Ukraine to join.
He was speaking alongside Olha Stefanishyna, Ukraine's Deputy Prime Minister with responsibility for European integration, who is pushing for speedy EU membership.
They were among the 1,000 delegates attending a conference in Dublin of the Alliance of Liberals and Democrats for Europe (ALDE) - a political grouping of which Fianna Fáil is a member.
A decision on whether to grant Ukraine membership status is expected to be made by member state leaders at a European Council meeting later this month.
Mr Martin said this would be "a very significant decision in itself" and "a very significant message to the Ukrainian people that you are part of the European family".
He added: "Already if you look at the interaction between the EU and Ukraine, in terms of customs and in terms of the welcome across the European continent for Ukrainian people, it is very clear to me that the future of Ukraine is within the European Union."
One argument that has been put forward against quicker accession has been that it would be unfair on some western Balkan nations, for whom accession has been stalled for some time.
But the Taoiseach said that he had been critical "before any war" about the slow pace of progress, particularly in relation to North Macedonia and Albania.
"I believe we need an acceleration of the accession process more generally," he said.
"Europe cannot complain about Russian manipulation of countries who are on the cusp of joining the EU, while being too passive and lacking proactivity in terms of the enlargement process.
"I am of the view that we need to look at a faster, more accelerated process, and there is significant reflection going on within Europe about all of this," Mr Martin said.
In relation to Ukraine in particular, he said there will be engagement, as there was for quite a considerable time with Ireland before it joined, but "the shortest possible timeframe is what I would be looking at.
"Because I think we are at a historic moment now, the whole of Europe and democratic states are saying enough is enough in terms of authoritarian regimes.
"Democracy cannot forever be in retreat and the most effective way for democracies to strengthen and to hold the line is to be together and to work collectively," he said.
Olha Stefanishyna, who met with the Taoiseach at the congress, said Ukraine needs concrete decisions around membership, rather than political promises.
She referred to the 1994 Budapest memorandum, under which Ukraine gave up its nuclear weapons, and the 2008 promise of future membership of NATO, as pledges that had not been fulfilled.
"Since that time, we've had three wars on European soil, two of which are now taking place on our territory.
"So we've submitted the application, to be integrated to European Union, we need promises to be materialised into concrete decisions as a candidate status."
Ms Stefanishyna also praised Ireland for its support for Ukraine.
"I want to praise your personal commitment and the commitment of the whole Government to host warmly the Ukrainian people, the people who are running out of their houses and homes to survive the war, and particularly grateful to the Irish people, the hospitality and the warmth with which you mobilised your support," she said.
Ms Stefanishyna asked that Russian officers be held accountable for their actions within Ukraine.
Her speech to the ALDE congress received a standing ovation from delegates.
