Ms Berejiklian will also resign from the NSW Parliament as soon as a by-election for her North Sydney seat, Willoughby, can be held.
She will remain prime minister until the Liberal Party elects its new leader, with treasurer Dominic Perrottet leading the way.
Perrottet said Friday that he would speak with his family and colleagues in the coming days about “how I can best serve the people of NSW”.
He said Ms Berejiklian was one of NSW’s best Prime Ministers ever.
Planning Minister and Pittwater member Rob Stokes will throw in his hat and is described as a key ally to Ms Berejiklian.
So is Environment Secretary Matt Kean, who was with her when she announced her resignation and is believed to be another contender.
Tourism Minister Stuart Ayres is also in the mix, and if he were to become party leader, the 40-year-old would be the first from an area outside the north and east of Sydney in nearly two decades.
Transport Secretary Andrew Constance and Attorney General Mark Speakman have also been named as possible contenders.
Ms Berejiklian endured wildfires, drought and storms and navigated COVID-19, but after four and a half years in the top job, she was unable to beat ICAC.
The anti-corruption watchdog says it is investigating whether Ms Berejiklian was “exercising public functions” in a conflict situation given her secret five-year relationship with ex-MP Daryl Maguire, revealed during ICAC hearings in late 2020.
Maguire is accused of abusing his public office between 2012 and 2018.
A weary Ms Berejiklian said on Friday she had “no choice” but to resign as she was unable to step aside temporarily and resume her role after the investigation.
“The people of NSW need certainty about who their leader is during these challenging times of the pandemic…I cannot predict how long it will be before ICAC completes this investigation, let alone issues a report.”
She also said her resignation “couldn’t have happened at a worse time” as the state prepared to exit months of COVID-enforced lockdowns in less than two weeks.
The 51-year-old continues to deny that he did anything wrong.
“History will show that I have always performed my duties with the highest degree of integrity on behalf of the people of NSW, whom I have been privileged to serve,” she said.
Prime Minister Scott Morrison praised Ms Berejiklian’s “heroic” qualities, saying she was a “best friend” and the trust of the community.