There have been furious scenes in the Dáil amid an ongoing row over a climate bill and the Government's use of so-called 'money messages'.
The sitting was briefly suspended following disagreements over the week's order of the business, as the Government faced accusations of acting in an "undemocratic" manner.
It comes after the Government's decision to block Bríd Smith's Climate Emergency Measures Bill, which aims to stop any further oil and gas exploration in waters off Ireland.
The bill has twice been backed by a majority of Dáil TDs.
However, the Government is bringing a rarely-used Parliamentary rule into play to block it from moving forward.
Under the Constitution, any piece of legislation that could cost the State money requires a “money message” signed by the Taoiseach.
By refusing to issue the money message, the Government is ensuring the bill cannot move forward to Committee stage.
The issue was brought up by Deputy Smith during leaders' questions, who claimed the Department of the Taoiseach was "heavily lobbied" over climate issues.
Addressing the use of money messages, she claimed: "The truth is that your department told the Ceann Comhairle that there was a money message needed on this bill because we would lose economic benefits to this country.
"In the lifetime of Corrib [pipeline] from 1992 until it dies in 2030, we will not have received a penny in tax or royalties back to this State from the Corrib basin."
She also cited a claim the Government would have to "pay back the application fees to the companies if my bill passed" - but suggested that claim was contradicted by an answer to a parliamentary question from the Taoiseach's own department.
She accused the Taoiseach of "lying" to 15,000 students about climate change commitments.
Deputy Smith was asked by the Leas-Cheann Comhairle Pat The Cope Gallagher to withdraw any accusation of 'deliberate lying', which she did while also suggesting there were 'mistruths'.
The People Before Profit TD also highlighted a meeting between the Taoiseach's adviser John Carroll and former government press secretary Feargal Purcell, who now serves as a lobbyist through his public relations work.
In the Dáil, Deputy Smith asked the Taoiseach: "When did the meeting between Mr Purcell and Mr Caroll of your office take place? What was discussed?
"The timing of that meeting is very important."
The Taoiseach said: "Lobbying is not a nefarious activity - it is part of democracy. We are all lobbied all the time.
"I checked today - there is no record of the meeting because there was no meeting in the Department of the Taoiseach between the two people you mentioned.
"The lobbyist in question asked my adviser to meet him for coffee - he didn't tell him what the reason for the meeting was."
"Over the coffee, he raised the [climate bill] issue, and he declared it in the lobbying register."
He added that the meeting happened on May 2nd 2019 - stressing: "I don't know how long it [was], or how much the coffee cost, or who paid for it."
The Taoiseach also said that a decision on whether a money message is required is one for the Ceann Comhairle.
Meanwhile, a number of opposition TDs insisted the issue of the use money messages should be debated this week - the final week of the Dáil before the summer recess.
The Green Party's Eamon Ryan accused the Government of acting in an "unconstitutional way".
He argued: "This Government has treated the order of business of this House in a way that is completely undemocratic".
Deputy Ryan said the blocking of the climate bill was the "worst egregious example".
Solidarity's Paul Murphy brought up the subject again shortly after.
He insisted: "[I don't think] we can finish the business of the Dáil for the summer without dealing with this issue - over 50 bills which have been supported by a majority in this House, and the Government is undemocratically blocking it.
"We simply cannot proceed in this way, Leas-Cheann Comhairle."
As Deputy Murphy continued to raise his objections, Deputy Gallagher suspended the Dáil for five minutes.