Leo Varadkar said that he was confident that the EU and the UK would be able to resolve the border issue despite the looming deadlines on a deal.
The UK has yet to present customs proposals in written form to EU negotiators following a summit in Sofia, Bulgaria earlier this month.
Mr Varadkar made the comments after a bilateral meeting with Belgian prime minister Charles Michel in Dublin.
He said the EU-27 needed to see significant and substantial progress on the text of the backstop before the June European Council meeting if Europe had a chance of making the October deadline for a deal.
Apprentice Boys of Derry: new era of respect makes for enjoyable ‘Relief’ parade
Feile organisers asked if they have warned Wolfe Tones about leading young people in pro-IRA chants
Thousands expected to take part in 'Derry Day' this weekend
DUP MP calls for probe into Sinn Fein MP’s Twitter post
Brexit: There’s a fundamental con trick being played over Liz Truss’ Northern Ireland Protocol Bill says Lord Empey
“We don’t yet have firm proposals that are in black and white that we can negotiate on,” said Mr Varadkar.
“That’s what we’re still waiting for.”
The taoiseach said Brexit was less than a year away and that progress needed to be made.
“The withdrawal agreement is going to be a legally binding agreement so we really need to see it written down now, written down in a form that’s operable and legally implementable,” Mr Varadkar said.
“We don’t yet have that from London.”
Mr Varadkar insisted there would be no physical checks at the border.
“We define that as there not being any physical infrastructure or associated checks or controls,” Mr Varadkar said.
“If technology was to involve cameras, for example, that is not something we could accept because that’s the physical manifestation of a border.”
He added: “Certainly we are making no preparations for a hard border between Ireland and Northern Ireland because we don’t believe it will happen.”
The Belgian PM visited the border between Ireland and Northern Ireland on Thursday morning.
Mr Varadkar said they discussed the Good Friday Agreement and the need to protect it in all its parts.
Mr Michel said Ireland had the EU and Belgium’s support in retaining an open border.