Berejiklian sworn in as NSW's 45th Premier

Gladys Berejiklian has been officially sworn in as NSW's 45th Premier.

Ms Berejiklian, 46, took the oath of allegiance at a ceremony at Government House in Sydney on Monday afternoon shortly after her predecessor Mike Baird formally tendered his resignation.

The outgoing treasurer's Armenian immigrant parents, Krikor and Arsha, and her two sisters had front-row seats at the ceremony which took place after Ms Berejiklian was elected unopposed as NSW Liberal Party leader earlier in the day.