NSW Treasurer Matt Kean says he is "humbled" to have been voted the new deputy leader of the state's parliamentary Liberal Party.
Mr Kean was elected unopposed in a party room meeting this morning.
The decision follows former deputy leader Stuart Ayres's resignation last week.
Government whip, Nathaniel Smith, announced Mr Kean's deputy leadership bid had been successful just after 10am this morning.
"I'm happy to announce there was only one candidate who stood for election," he said.
"And our new deputy leader of the parliamentary Liberal party, was elected unopposed, is the honourable Matthew Kean, Member for Hornsby, Treasurer of New South Wales and Minister for Energy."
Mr Ayres last week stepped down from his deputy leader and ministerial roles amid the fallout of former deputy Premier John Barilaro's appointment to a US-based trade role.
Mr Ayres, the Penrith MP, denies any wrongdoing.
Mr Ayres's close friend, Transport Minister David Elliott, had previously flagged his intention to run for the deputy leadership but pulled out of the race yesterday.
Mr Elliott told Nine radio he withdrew at the request of Mr Perrottet, who he said had laid down a "demand for unity" ahead of today's meeting.
"I told him I respect his wish to pick his own deputy," Mr Elliott said.
Premier Dominic Perrottet praised Mr Kean's work as Treasurer during a media conference, saying he had this year delivered "one of the best budgets ever handed down in this state".
"Where Matt's real qualities are, in my view, and why he was elected today, is his passion and zeal for reform to set up a brighter future for the people of our great state," he said.
Mr Perrottet said he spoke to both contenders on Monday about "the importance of unity".
"They understood that," he said, adding that Mr Elliott's decision to withdraw from the contest was a "selfless" one.
"I think the sense in the party room today was incredibly strong," the Premier said.
"The entire party room coming together in supporting Matt Kean as deputy leader."
Mr Kean said he was "humbled" to have been endorsed after joining the party more than 20 year ago.
"My role is to support the Premier, to support the team, and make sure we work to build a stronger, brighter and more prosperous future for every single person in New South Wales," he said.
"I'm honoured and proud to serve in this role."
Mr Perrottet said Mr Elliott was not present in the party room today because he was on sick leave.
Mr Perrottet today confirmed Bruce McClintock, SC, would conduct a legal review into whether Mr Ayres complied with the Ministerial Code of Conduct in relation to the appointment of Mr Barilaro.
He said it was important that there was "complete public confidence" in the recruitment process for high-powered roles.
The Premier also said if he had his time again, he would have asked Mr Barilaro not to apply for the US trade role.
