"Led by members of the reactionary right, the coup was aided by many parliamentarians who exchanged their vote for a change of leadership in exchange for their individual promotion, pre-selection endorsement or silence," she told parliament.
"Their actions were undeniably to themselves, their position in the party, their power, their personal ambition – not for the Australian people we represent, not for what people voted for in the 2016 elections, not for stability."
Ms Banks kept the government in the dark about her intentions and surprised her colleagues with her statement to Parliament on Tuesday at the time that Morrison and Treasurer Josh Frydenberg were in the courtyard of the prime minister to announce his budget plan.
She pledged support to the government in trust and supply, but signaled she could run as independent in the upcoming election, fueling speculation as to whether she would run her headquarters in Chisholm or compete against the Liberal Party elsewhere.
The government is preparing for a labor attempt to challenge Mr. Dutton with the help of the strongest numbers on the bench, seeking to refer the Home Secretary to the Supreme Court, claiming that he has a beneficial interest in crèches that receive money from the community.
Although lawyers question whether this disqualifies Dutton from Parliament, according to section 44 of the Constitution, the government expects Labor and Greens to get support from bankers to seek a court ruling.
In an attempt to thwart this prospect, the government identified Labor MPs Mike Freelander, Tony Zappia and Anne Aly as equally vulnerable to section 44, arguing that they should be referred to the court if Dutton is.
Morrison kept his focus on the economy on Tuesday by announcing plans for a December 17 budget update and a full budget on April 2, promising they would reveal a surplus and confirm the Coalition's economic management.
The timeline, released by Fairfax Media on Monday, puts the nation on the path to an election May 11 or May 18 in a campaign that begins with a major economic statement and an improvement in Commonwealth finances.
The government is on its way to a deficit of $ 4.9 billion this year, but Morrison's language has suggested an improvement until May to prove that the Coalition is delivering results.
"It will be a budget that is the product of years of hard work by our government, of successive prime ministers, who have ensured that we are on the way to delivering a surplus budget, which is what we promise the Australian people that we would do," Morrison.
The Coalition won 76 seats in the lower house in the 2016 election, but lost that narrow majority in the Wentworth election when independent Kerryn Phelps replaced Mr. Turnbull and cut government seats to 75.
The government has chosen one of its own MPs, Tony Smith, to sit as president and therefore has only 74 votes in the House floor.
The loss of Ms Banks reduces to 73 and means that the government will be in a minority position in all legislation.
Ms Banks delivered her remarks to the chamber of her chair among her liberal colleagues, but moved to the counter for question time, where she joined Dr Phelps, Cathy McGowan and Rebekha Sharkie – three women in seats formerly held by Coalition.
"My sensible and centralized values, the belief in economic responsibility and always putting people first and acting in the interest of the nation have not changed," Banks said.
"The Liberal Party has changed, largely because of the actions of the reactionary and regressive right who speak and speak to themselves instead of listening to people."
Defense Minister Christopher Pyne said Banks would have to "shoulder the consequences of that decision," but being in a team meant that a parliamentarian did not always get what he wanted.
Former Queensland premier Campbell Newman said it was a "shameful effort" and it seemed to be "all about" Mr. Turnbull.
"It's cowardly, it's selfish and it comes with an agenda," Newman told Sky News. "In my opinion, it has something to do with Peter Dutton."
Liberal Congressman Craig Laundy, another who supported Mr. Turnbull during the leak, said Banks was a valuable colleague.
"I'm sad about the decision she made today, however, having spent a lot of time with her position, the events of the leadership change, I'm not surprised because I & # 39; I saw firsthand the impact it had on it, "said Mr. Laundy.
David Crowe is the main political correspondent for the Sydney Morning Herald and The Age.