The Liberal party has moved to disrupt the cycle of leadership instability by resolving that sitting prime ministers can in future only be removed by a two-thirds party room majority.

Federal Liberal MPs voted to change the rules over the selection of party leaders in a snap party room meeting on Monday night, even though Scott Morrison has previously argued that “regulating for culture is never effective”.

Morrison told reporters on Monday night that he understood the “frustration and disappointment” felt by voters about recurrent leadership coups in Canberra. “We acknowledge it, and we take responsibility for it. We have listened and we have acted.”

The prime minister said MPs were sick of the coup culture, and Australian voters were sick of the coup culture, “and it has to stop”.

The prime minister told reporters the party room had resolved overwhelmingly that an elected Liberal party leader who goes to an election and wins will remain prime minister for the full parliamentary term.

That rule would only be overturned by a two-thirds majority. Morrison noted that “such a majority is rarely, if ever, achieved”.

The rule change means that the newly adopted convention does not apply to Morrison now, because he has not yet won an election as prime minister.

Morrison said the rule change was an acknowledgement that the Liberal party needed a change in culture, and he said if voters returned him to the top job next year “I will remain as prime minister”.

The rule change was developed by the party whips, and Morrison consulted the former prime minister John Howard, but not the man he replaced, Malcolm Turnbull, about the shift prior to Monday night’s meeting.

After taking over as Liberal leader in August after the conservative-led coup against Turnbull, Morrison played down the need to change the rules on electing the leader, telling reporters that politics needed a “change in culture” and “regulating for culture is never effective”.

In the wake of the spill Morrison was publicly urged by colleagues including now environment minister Melissa Price, MPs John Alexander and Scott Buccholtz and federal Liberal president Nick Greiner to change the rules.

Unveiling his new-look ministry on 26 August, Morrison said that rules on electing the leadership “are things that members of our party room will discuss from time to time”. He added that: “Regulating for culture is never effective.”

Speaking on Monday night, Morrison attributed his change of heart to reflecting on the will of the Australian people.

On the day of the Liberal leadership spill the former Labor prime minister Kevin Rudd urged the opposing party to “adopt a rule change to prevent rolling political chaos … for the nation’s good”.

For the nation’s good, I’d urge Liberal Party to adopt a rule change to prevent rolling political chaos. Our 2013 rule change (requiring 50% vote of MPs, 50% of ALL party members) means you can’t just launch a coup at the drop of a hat. It’s helped give Labor 5 years of stability — Kevin Rudd (@MrKRudd) August 24, 2018

Rudd has said that his decision to require a super majority of at least 60% of the Labor caucus – or 75% when in government – to depose the leader had “stabilised the Labor party in the last five years”.

At the launch of the second volume of his autobiography in October, Rudd even suggested former deputy Liberal leader Julie Bishop should push for a rule change to erect “one giant speed bump to prevent midnight coups”.

Bishop reportedly told The Australian after the event that she was not sure the idea would catch on in the Liberal party.