"Labor, under my leadership, starts its journey in rebuilding faith and trust with you." Ms McKay also defeated Mr Minns in the 50-member caucus vote, which was held on Saturday morning, securing 29 votes to Mr Minns' 21 votes. Kogarah MP Chris Minns put up a tough fight. Credit:AAP Her victory brings to an end the three-month long leadership vacuum in NSW Labor, following the resignation of former leader Michael Daley following the March state election. Ms McKay will pitch her vision for government against that of Premier Gladys Berejiklian - the first time NSW has had female party leaders in government and opposition simultaneously

It is the first time the process has been used to elect a NSW Labor leader, under the same rules introduced by former Labor prime minister Kevin Rudd in 2013, which gives rank-and-file members and the caucus each a 50 per cent say in the outcome. Ms McKay and Mr Minns endured an hours-long wait for the verdict, as Labor scrutineers and officials spent most of the day verifying the rank-and-file ballots against party membership lists. Ms McKay won 63 per cent of the more than 11,000 member votes, which amounted to a 61.5 per cent turnout of the party's rank-and-file. Despite the delay, the day was not without drama, with tensions boiling over earlier in the morning as the caucus vote was under way inside Labor's party room at NSW Parliament House. Outside the caucus room, and in full view of the assembled media, Bankstown MP Tania Mihailuk accused upper house MP Mark Buttigieg of "standing over" Shellharbour MP Anna Watson while the vote was taking place.

In an exchange heard by journalists standing 20 metres away, Ms Mihailuk yelled at Mr Buttigieg: "Don't stand over a woman." Mr Buttigieg responded, yelling: "Don't try that shit on with me, Tania." Both MPs gave differing accounts of the incident moments earlier inside the caucus room that led to their heated hallway clash. Mr Buttigieg, who voted for Ms McKay, claimed he had a "pre-existing pairing arrangement" with Ms Watson in which they agreed to show each other their votes, and denied there was any attempt to intimidate her. "I literally walked over to her and showed her my vote. I leaned over to show her my ballot paper and I looked at hers," he said.

Loading Ms Watson, who entered the caucus room with Mr Minns and his supporters, declined to comment, telling the Herald: "I don't talk about what happens in the caucus room." Ms Mihailuk, who backed Mr Minns, claimed she watched Mr Buttigieg "fully standing over" Ms Watson in an attempt to see which way she was voting. "There's no way that's a normal pairing arrangement. He was fully standing over her. She was sitting on the lounge and he was standing right on top her," she said. "[Ms Watson] looked really intimidated to me. I checked if she was OK, and she said she wasn't OK."

Ms Watson confirmed Ms Mihailuk had inquired after her wellbeing, and said she left the party room shortly after she cast her vote to return home to care for an ill family member. Auburn MP Lynda Voltz, who was sitting next to Ms Watson in the caucus room, said she didn't see anything unusual in the interaction between Mr Buttigieg and Ms Watson. Acting leader Penny Sharpe will face a challenge to the deputy role next week. Credit:AAP "I was sitting next to Anna and if she was being intimidated, I would've noticed," Ms Voltz said. "She certainly wasn't." Ms McKay's election will trigger a fresh round of internal campaigning, which will begin almost immediately as MPs start jostling for frontbench positions.

Her victory will also be a factor in determining the deputy leadership position, which will be elected by the caucus at another meeting on Tuesday. Swansea MP Yasmin Catley, Ms McKay's chief lieutenant during the leadership campaign, is expected to challenge acting leader Penny Sharpe for the role, in a move that will split the party's Left faction. Another of Ms McKay's key backers, Adam Searle, is expected to retain his position as the party's leader in the upper house. But Walt Secord, a key supporter of Mr Minns, could struggle to hold onto his position as deputy leader in the upper house.