Prime minister’s leadership appears terminal with resignation of key frontbenchers and conservatives lining up behind Dutton

The Dutton camp is continuing to foment the Coalition’s leadership crisis, with ministers who supported the former home affairs minister in Tuesday’s snap leadership ballot tendering their resignations as a prelude to a second challenge.

Frontbenchers, including Michael Sukkar, Angus Taylor, Zed Seselja and Queenslander James McGrath – who is a former member of the prime minister’s inner circle – offered to quit their posts on Tuesday night after outing themselves as Dutton supporters, the first of a sequence of expected departures.

Turnbull refused their offers, hoping instead to heal the wounds. Concetta Fierravanti-Wells wrote a scathing letter to the prime minister saying conservative voters felt their voice had been “eroded”, and on Wednesday morning she considered herself resigned, but she hasn’t spoken to him yet.

The trade minister, Steve Ciobo, was also expected to offer his resignation on Tuesday evening, but later tweeted the party room had made a resolution about the leadership, and “we must unite to defeat Labor”.

The government’s implosion gathered intensity throughout Tuesday, with Malcolm Turnbull spilling the Liberal party leadership in a pre-emptive strike to check Dutton’s momentum.

The prime minister prevailed in the head-to-head battle, and the leadership group held for Turnbull, triggering Dutton’s resignation from cabinet.

But Turnbull’s position now looks terminal. The conservative faction largely shifted en masse to Dutton, fielding 35 votes for the challenger, including cabinet ministers and occupants of the outer ministry, despite the lack of active canvassing.

After the result, Dutton repeatedly refused to rule out a second tilt at the leadership, with some MPs believing that could come later this week, and he reserved his right to speak out from the backbench.

Framing his opening pitch to colleagues as a leadership alternative, Dutton told Sky News the government’s messages to voters needed to be more succinct, and he also put cutting immigration squarely on the table. “It’s clear the Australian public have a view that the migration number is too high.”

The conservatives that have lined up behind Dutton since the government’s rout in the Longman byelection want immigration elevated as an election issue in an effort to peel back support from One Nation and other populist insurgents.

Dutton also made it clear he intended to use his time out of cabinet to soften his strong man image, and at one point suggested if it were up to him, he would have removed asylum seekers from Manus Island and Nauru.

In a message crafted for internal consumption, Dutton declared he was not Tony Abbott’s “puppet” – which is the view of the group of moderates holding for Turnbull, who believe he has been willingly coopted in Abbott’s crusade to bring down Turnbull.

But while attempting to create distance between himself and Abbott, Dutton also refused to rule out returning the former prime minister to the cabinet in the event he became party leader.

Dutton’s scene setting was followed by the string of ministers offering their resignations on Tuesday night, intensifying the sense of crisis, and softening the ground for a second tilt.

Senior players in the government characterise the current power struggle as a full conservative takeover of the Liberal party, with one terming that “a perfect recipe for political annihilation”.

The frustrations of marginal seats holders and some Turnbull backers boiled over in the regular government party room meeting immediately following the leadership spill.

Abbott, who told colleagues the government needed to appeal more to small “c” conservatives during an intervention when he sought more detail about the LNP’s poor performance in the Longman byelection, copped a blast from MPs including the Queenslander Warren Entsch for his persistent wrecking tactics.

Entsch quoted Abbott’s “no sniping, no wrecking” pledge when he was deposed as Liberal party leader in 2015 back at Abbott. According to party room sources, the National Damian Drum declared during the discussion: “This is just fucked.”

A ReachTel poll commissioned by the activist group GetUp! suggests a move to Dutton would be high risk for the government. The poll says 46% of voters would be less likely to vote for the Coalition if they adopted a more conservative policy platform, and half the sample said they would be less likely to vote for the government if Dutton became leader.

Victorian Liberals are particularly concerned that a change of leadership would trigger a bloodbath for the government, putting seats in play that are currently regarded as winnable.

Some government MPs also point out the Liberal party is not ready for any snap poll that the insurgents might trigger if they succeed in toppling Turnbull, with the party strapped for cash, and Dutton and his supporters lacking the deep links into corporate Australia to fill the party’s coffers for a national battle.

Dutton could also face trouble with crossbenchers in the lower house, with both Cathy McGowan and Rebekha Sharkie reserving their position on confidence and supply in the event a leadership coup triggers resignations of government MPs from the parliament.

Turnbull appealed for unity, an appeal backed by his deputy, Julie Bishop. Bishop told the ABC there was “a debate within our party room about the way we’re connecting with the Australian people”, but unity would allow the government to stabilise and build momentum.

She said a majority of the Liberal party room “endorsed Malcolm Turnbull as the leader of our party. I respect the majority view of the party room, and I hope all my colleagues do as well”.

Asked whether she would put her own name forward to give her colleagues a more palatable alternative to Dutton in the event the current crisis escalated to a second confrontation, Bishop didn’t answer directly, but said she wasn’t contemplating that option.

Guardian Australia understands Bishop would not seek to serve on the front bench if Dutton prevailed in a leadership contest.

• with Paul Karp