A 1970-batch IFS officer, Ponappa will also hold the post of Secretary in the National Security Council Secretariat, the country's strategic policy making body.
The name of Ponappa, who retired in June 2006 after serving as Ambassador to The Hague, was cleared by Appointments Committee of the Cabinet, headed by Prime Minister Manmohan Singh.
Her tenure will be for two years.
The appointment of Ponappa comes at a time when NSCS was being revamped following busting of a major spy racket in 2006.
She is the first Deputy NSA appointed in Congress-led United Progressive Alliance government. The post was earlier held by Satish Chandra during the NDA regime.
The ACC also appointed Christy L Fernandez as the new Tourism Secretary in place of Ashok Kumar Mishra, who is due to retire by end of this month.
Fernandez, a 1973 batch IAS officer of Gujarat cadre, is at present Additional Secretary in the Department of Commerce.
