The Prime Minister also held the unified Ministry of External Affairs and Defence until 1977, when J.R. Jayewardene's government adapted two separate ministries, forming the Ministry of Defence and the Ministry of Foreign Affairs.
Perdana Menteri juga memegang Kementerian Urusan Eksternal dan Pertahanan sampai 1977, ketika pemerintahan J.R. Jayewardene menjadikannya dua kementerian terpisah, dengan membentuk Kementerian Pertahanan dan Kementerian Urusan Luar Negeri.