Mary Manson Dreaver MBE (née Bain, 31 March 1887 – 19 July 1961) was a New Zealand politician of the Labour Party.

Mary Dreaver was born in Dunedin in 1887, the oldest of 13 children of Alexander Manson Bain, a Scottish Presbyterian cabinetmaker and trade unionist, and his Irish Catholic wife Hanna Kiely.

[8][9][10] In 1933 a visit by her to the hospital kitchen and claims of long hours and "sweated labour" there aroused controversy on the board.

[15] In 1941 she won the Waitemata electorate when a by-election was held after the death of the previous Labour Party MP, Jack Lyon.

[18] Dreaver was defeated in the next (1943) general election, by the National Party candidate, Henry Thorne Morton.

They were appointed by the First Labour Government in 1946 (after a law change in 1941 to make women eligible); they served to 1950 when the Legislative Council was abolished.

[21] In the 1946 New Year Honours, Dreaver was appointed a Member of the Order of the British Empire for services in connection with recruiting for the Women's Land Army.