The Labor Party has avoided an acrimonious battle for the Victorian leadership, with Deputy Premier Jacinta Allan emerging triumphant in a tense race to replace Daniel Andrews.

Allan’s victory on Wednesday afternoon came only after a surprise challenge from Public Transport Minister Ben Carroll that threatened to leave Victorians waiting as long as six weeks before their new premier was decided.

In the end – after lengthy and sometimes heated negotiations on Wednesday – Allan was elected unopposed. Carroll will be her deputy.

“Can I say 24 years ago – almost to the day – when I walked into this place as a much younger woman from regional Victoria, I never expected to have this length of service,” she said shortly after the decision was revealed.

“It is such a deep honour and privilege to be in the position, to be heading to Government House and to be sworn in as premier.”

Carroll had earlier appeared set to challenge Allan for the Victorian party leadership following the shock resignation of Daniel Andrews on Tuesday.

On Wednesday morning, he arrived at a Labor caucus meeting flanked by police minister Anthony Carbines, who is also from Labor’s right faction.

Allan is from the left faction and became Deputy Premier in June 2022. She was an Andrews protege, and nominated herself for the top job on Tuesday, hours after he resigned.

Labor’s caucus meeting was meant to start at midday but by 12.30pm there was still no sign of Andrews or Allan. Andrews eventually arrived after 1pm, to an outburst of applause from caucus colleagues.

Carroll was later seen leaving the meeting room while talking on his phone. He refused to answer questions.

Wrangling and negotiations continued into Wednesday afternoon, with tensions high.

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Treasurer Tim Pallas had nominated to be Allan’s deputy, while Carbines stood as a potential deputy to Carroll. The Australian reported one Labor source describing the emerging battle as “World War III”.

“It’s incredibly embarrassing for Jacinta and Dan. A total mess,” they said.

Other MPs told the ABC that the complex negotiations risked stability, with one describing Carroll’s challenge as “treachery”.

If more than one contender for the leadership was confirmed, it meant Victoria’s new premier would not be known on Wednesday because ALP rules stipulate a leadership ballot would then be needed. That could have taken up to six weeks.

In the end, deals were done and Allan emerged as the victor, with Carroll to take the deputy’s role.

Earlier, MPs remained tight-lipped as they entered the caucus room, with Environment Minister Lily D’Ambrosio saying the party had a process to go through.

“There’s caucus meeting this morning, I’m looking forward to joining the caucus with my colleagues and letting the usual caucus process run its course,” she said.

Asked if she had the support of her Labor colleagues, Allan said she would respect them and let the usual process run its course.

Arriving at parliament on Wednesday, Pallas had refused to rule out a tilt for the deputy role.

“I’m still consulting with my colleagues about that and, of course, it’s important to see who the leader is and that person get the opportunity to pick the person they want to be deputy,” he said.

Allan, the MP for Bendigo East, will become Victoria’s first female premier since Joan Kirner stepped down in 1992. Allan described her as a “mentor”.

“It’s not lost on me that I am only the second woman to lead this state,” she said.

“Leadership takes on different shape sand sizes. Women have a role and a place in our community … there is a place for women at every single decision-making table.”

Former federal opposition leader Bill Shorten said Allan would ensure all Victorians were represented on Spring Street.

“She’s a very highly successful, accomplished woman leader in her own right,” Shorten told ABC Radio National.

“She comes from the regions, she’s a very experienced politician.”

Andrews announced his decision to step down at a press conference on Tuesday. He cited thoughts about life after the top job, hinting he could work in the private sector after taking time off.

Andrews became premier in November 2014, booting out a first-term Liberal government, and led Labor to victories in 2018 and last year.

During the 2022 campaign and the months after, he repeatedly said he would stay for the full four-year term. His change of heart was a recent decision, he said.

Prime Minister Anthony Albanese told ABC Radio Melbourne on Wednesday that Andrews had been a strong leader and passionate Victorian.

– with AAP