The New South wales Premier will step down as NSW Premier and will resign from her seat in the electorate of Willoughby.
She will resign from parliament and will trigger a by election.
Ms Berejiklian said she was “pained” to resign and said the ICAC investigation came at the “worst time”.
The state’s corruption watchdog revealed it was investigating her.
The ICAC is probing whether Ms Berejiklian breached public trust when she awarded grants to several community organisations between 2012 and 2018.
It will hold public hearings later this month to investigate whether there was a conflict between Ms Berejiklian’s public duties and private interests when she was in a personal relationship with then-MP Daryl Maguire.
Liberal party sources said ministers have already started to “do the numbers” for who takes over the leadership.
The ICAC has announced it will hold a public inquiry on Monday October 18 relating to Ms Berejiklian and whether her conduct had involved a breach of public trust.
