Member for Kiama Gareth Ward has stepped aside after news emerged that he was being investigated over historical allegations of sexual violence-related offences.
Mr Ward, who denies any wrongdoing, stood down from both his position as Minister for Families, Communities and Disability Services, and the Liberal party room.
He said he had no knowledge of any investigation.
This came an hour after reports first surfaced in Sydney media that a NSW politician was being investigated by police over sexual violence-related allegations from 2013.
Mr Ward said he first found out about the allegation when he was contacted by a journalist today.
Police had not named the MP under investigation or commented in detail. Mr Ward issued a short statement about 5.25pm.
"Today I have been made aware by a journalist of an investigation into me by NSW Police," the Liberal MP said.
"I have not been contacted by police in relation to any allegations.
"I deny any wrongdoing.
"Until this matter is resolved, it is appropriate I stand aside from my role as Minister. I will also remove myself from the Liberal Party room.
"I will not be making any further comment at this time."
Premier Gladys Berejiklian, with a second MP accused of sexual offences this year, supported Mr Ward's decision.
"I was made aware through media reports today that an MP is under investigation by police," she said.
"I have subsequently received advice from Minister Gareth Ward of his decision to step aside as minister and sit on the cross bench while there is speculation about his future.
"I support his decision. The Attorney-General [Mark Speakman] will act in Mr Ward's portfolio responsibilities."
Mr Ward was first elected to represent the seat of Kiama in 2011.
In March Member for Upper Hunter Michael Johnsen resigned after accusations of sexual assault and sexting were made against him.
Mr Johnsen has denied the allegations.