Regulations for the Navy Part IIICentral Regulations · 1957
(1) Officers who have passed a voluntary specialist course or are otherwise considered suitable may volunteer for temporary service in the Indian Navy, should their services be required in lieu of Regular Officers of the Indian Navy.
(2) No temporary appointment shall, however, be made without the prior approval of the Government of India and the number of such appointments and the periods for which they are made shall depend on vacancies available in the authorized cadre of the Indian Navy.