 Sri Temasek is a two @-@ storey detached house built in 1869 which is sited within the grounds of the Istana in Singapore . During the island 's colonial era , it served as the residence of the Colonial Secretary or Chief Secretary . Since the establishment of the State of Singapore in 1959 , it has been the official residence of the Prime Minister of Singapore , though none of Singapore 's Prime Ministers has ever lived there . Together with the Istana , it was gazetted a national monument on 14 February 1992 . 
