Leo Varadkar has said EU leaders are 'not satisfied' with the progress that has been made in Brexit talks.
Speaking to Bloomberg during his visit to Canada, said it is hoped that the common travel area will remain, and stressed he is 'reassured' over the British government's commitments to the peace process in Northern Ireland.
However, he argued there has not been 'sufficient progress' in other areas, including calls to ensure there is no trade border on the island of Ireland.
During the interview, he also expressed concerns over the British government's approach to trade, despite their recent efforts to clarify their position.
He argued: "Where we're confused and puzzled is [over] what trade agreement does the United Kingdom want with the European Union?
"At the moment, they have the best trade deal possible, the best one imaginable - which is a customs union and access to the single European market.
"What they seem to be suggesting all along - really for the last 14 months now - is that they want to have all of the advantages of being in the EU, but none of the responsibilities or cost. And that's not a realistic position."
Mr Varadkar stressed that the UK will not just be leaving the EU, but also leaving trade deals between the EU member states and other countries.
He cited the controversial CETA [Comprehensive Economic and Trade Agreement] deal with Canada - which will begin coming into force in a month's time - as well as other trade deals between the EU and Japan & South Korea.
The Taoiseach added: "It's not yet clear to us what are these better deals that the British government really wants from Europe and other countries."
— Bloomberg (@business) August 22, 2017
The Taoiseach's comments came ahead of the British government's Northern Secretary James Brokenshire's arrival in Dublin.
Mr Brokenshire will hold talks with Foreign Affairs & Trade Minister Simon Coveney later today.