Leo Varadkar says he is unsure whether a breakthrough could come this week to solve the issues around the Northern Ireland Protocol.
But the Taoiseach said a "huge amount of progress has been made" as he called for British prime minister Rishi Sunak to be given "some time and space" to consult with the Conservatives.
There has been speculation that the two sides are close to agreement.
The DUP are refusing to reenter devolved government at Stormont until unionist concerns over the Protocol are addressed.
This has resulted in a year of political paralysis in the North.
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Sinn Fein vice president Michelle O'Neill said that the region has been in "limbo for too long".
Ms O'Neill, who is poised to become First Minister when Stormont returns, said: "I think the time for doing a deal is now and we want to see the restoration of the [Northern Ireland] Executive in the aftermath of that."
She added: "This has always been an issue between the UK and EU side, they're the two negotiating partners, it's for them to reach an agreement.
"We have made our view very clear. We know that we need to maintain the Protocol and its protections, particularly for the all-island economy, and protection of the Good Friday Agreement."
British Health Minister Maria Caulfield, a Brexiteer who quit Theresa May's frontbench over her Chequers plan, urged colleagues to "support the prime minister".
"There isn't a deal done yet so all these rumours about ministers or MPs not being happy, I haven't seen the details, we have to give the prime minister that time and space to get these negotiations done," she told Times Radio in the UK.
But Jacob Rees-Mogg, a former cabinet minister and long-time critic of Mr Sunak, branded his tactics as similar to those that eventually led to the resignation of Theresa May as prime minister.
Mr Rees-Mogg joined Boris Johnson in urging Mr Sunak to press ahead with the controversial Northern Ireland Protocol Bill, effectively ripping up parts of the agreement with the EU, rather than seeking a deal which may not guarantee the return of a powersharing executive in Stormont.
On his Conservative Home podcast, Mr Rees-Mogg said: "There seems to me to be no point in agreeing a deal that does not restore powersharing.
"That must be the objective. If it doesn't achieve that objective, I don't understand why the government is spending political capital on something that won't ultimately succeed."
British government insiders still believe a deal could be struck in the coming days, but acknowledge it would slip to next week if not concluded by the one-year anniversary of the war in Ukraine on Friday. Mr Sunak told his cabinet meeting "intensive negotiations with the EU continue on resolving the issues with the way the Protocol was being enforced", No. 10 Downing Street said.
