Sinn Féin leader Mary Lou McDonald has said the party's motion of no confidence in Tánaiste Leo Varadkar was the only option left to them, as Taoiseach Micheál Martin failed to sanction him.
TDs will debate the motion of no confidence in Mr Varadkar in the Dáil later on Tuesday.
It comes after the Fine Gael leader confirmed he had sent a confidential GP agreement to the then-head of the NAGP, Dr Matt Ó Tuathail, while he was Taoiseach.
Last week, Mr Varadkar told the Dáil there was "nothing inappropriate" about his informal contact with the NAGP - but admitted it was an error of judgement to share the document without telling any of his Government colleagues.
"I do accept that the provision of the agreement by informal communicational channel to the president of the NAGP in the way that I did was not good practice," he said.
Ms McDonald told Pat Kenny her party had very little choice.
"The objective of the exercise is to establish that the Taoiseach, the person serving in the highest office in the land, does not leak confidential documents.
"The purpose of the exercise is to bring some real accountability into the equation.
"And by the way if the serving Taoiseach Micheál Martin had acted to sanction Leo Varadkar, we wouldn't have had to place this motion.
"As the opposition, the only option available to us is to actually put down this confidence motion and that's what they've done".
'A reckless act'
She said the party had hoped this type of behaviour was a thing of the past.
"It was a reckless act, it was something that the Taoiseach should not have done, I think it is something that brings into question the ability of whosoever occupies that office to hold a confidence."
"And bear in mind this was a sensitive negotiation, it was a long negotiation.
"The contract in question had some €210m of taxpayers' money at the heart of it - and when you negotiate with any party, when the State negotiates with any party, they have to negotiate in good faith.
"Leo Varadkar got that draft contract, he gave it to his friend and the facts are not in dispute".
"I'm absolutely astonished over the last week or more that that section of Irish political life - and the commentariat and the Irish establishment - who think that a Taoiseach leaking a confidential document to his friend is no big deal.
"I think if that's where we're at Pat, we are in big, big trouble.
"I think that that era that we had hoped was gone and consigned to the past - of closed circles and who knows who and who's friends with who - that has done huge damage to Irish society, that's not acceptable".
"Even if we are to be criticised for calling Leo Varadkar to account on this, it it my firm belief that we are doing the right thing.
"If we are going to get things right in Ireland, we have to stop that type of politics".
'Very likely' to be defeated
While Finance Minister Paschal Donohoe has said the no confidence motion is 'very, very likely' to be defeated.
He earlier told Newstalk Breakfast this must be viewed 'in the round' of Mr Varadkar's time in public office.
"I think it's very, very likely that it will be defeated.
"I think Government TDs and those who work with Leo, and who have done so for a while now, except two things.
"The first thing they accept is that the way in which this particular matter was handled fell short of the standards that Leo Varadkar has for himself.
"But the second thing I think they accept is that Leo has demonstrated the highest of standards in his time in public office on the management and leadership of a whole array of matters for our country.
"And I think this particular issue has to be seen in the round, and in the round of his normally exceptionally high standards".