Annie Isabel McLean was born in Andersons Bay, Dunedin, on 21 September 1868. She was the eldest daughter of George McLean, a merchant and, after Annie's birth, a politician and cabinet minister. Her mother, Isabella Holmes, was the daughter of Matthew Holmes, a member of the Otago Provincial Council and the Legislative Council. Her education in Dresden, Germany, and in England probably led to her later wide interest in international affairs.
Annie McLean married Charles Anderson Fraer at Warrington, north of Dunedin, on 8 January 1898. He was then a clerk in holy orders, and together they began work among Maori at Waikouaiti; they later moved to Tuahiwi, near Kaiapoi, where Charles Fraer was Anglican vicar of the surrounding parochial district from 1904 to 1918. Annie had gained nursing experience which proved invaluable and won her the confidence of the people. She and her husband were responsible for founding Te Waipounamu College for Maori Girls at Ohoka, in the same district. Annie Fraer continued throughout her life to be interested in Maori welfare, her Maori friends often seeking her advice. Although this part of her work was the least public it was the closest to her heart.
Annie and Charles Fraer moved to Christchurch in 1918, and Annie became well known for her involvement in women's issues. An energetic and forceful woman, capable of inspiring others, she was active in the National Council of Women of New Zealand, serving as vice president of the Christchurch branch (1922–23) and president (1924–27). She was then dominion president from 1927 until 1931 while continuing to be among the vice presidents of the Christchurch branch from 1927 until 1933. She was made a life member in 1937. During Fraer's active involvement, the NCW pressed for women to be appointed justices of the peace. When legislation to allow this was passed in 1926 Annie Fraer was among the first 18 women to be appointed. In the 1920s the NCW urged the government to appoint women to the Prisons Board: Annie Fraer was appointed in 1929.
Annie Fraer was one of four members of the NCW to attend the seventh quinquennial International Council of Women conference in Washington DC in 1925. A foundation member of the New Zealand National Branch of the Pan-Pacific Women's Association, she led the New Zealand delegation of 17 women to its first international gathering in Honolulu in August 1928.
Fraer also threw herself into other community activities. She was appointed to assist magistrates in cases coming before the Children's Court. In 1929 and again in 1931 she was elected to the Christchurch City Council and helped to obtain several playgrounds in Christchurch. A keen worker for peace, she was a founding member of a branch of the League of Nations Union of New Zealand in Christchurch. Always willing to speak for the league or to promote any of its humanitarian objectives, she was an active member of the executive and in 1938 was made a life member. She also became an active member of the Christchurch Women's Unemployment Committee during the depression.
Annie Fraer's many services were recognised in 1935 when she received the King George V Silver Jubilee Medal and later that same year was appointed an MBE. She died in Christchurch on 8 March 1939, and was survived by two daughters; Charles Fraer had died in 1932. Annie Fraer was remembered for her forceful personality and for her selfless work for a wide variety of causes and organisations.