Netto, who was serving as the Additional Chief Secretary (Home) and Secretary to Chief Minister Pinarayi Vijayan, replaced S M Vijayanad.
After assuming office at the Secretariat here, she told reporters that her efforts would be to take the officials together.
An IAS officer of 1981 batch, Netto had held various positions such as the State Tourism Director, Secretary in Tax, Irrigation and Transport departments, Cooperation Registrar and also District Collector of the state capital.