Amelia Bagley was born on 2 October 1870 at Dunedin, New Zealand, to Amelia Prictor and her husband, Benjamin Bagley, a chemist. Both Amelia and her sister, Mary, chose nursing as a career and neither married. Both achieved considerable prominence within the nursing profession. Mary became matron of St Helens Hospital in Wellington, while Amelia was to play a major part in the development of public health nursing in New Zealand.
A slim and attractive woman with dark hair and dark eyes, Amelia Bagley trained as a nurse at Dunedin Hospital from 1892 to 1895. The first decade of her career was spent in the hospital service, first at Auckland Hospital from 1895 to 1902, and then as matron of Masterton Hospital from 1903 to 1905. In 1902 state registration for nurses was introduced to New Zealand and she was registered in March of that year. After the passing of the Midwives Act 1904 Bagley entered St Helens Hospital in Wellington as one of its first trainees. She registered as a midwife in December 1905, and her certificate was one of the few signed by the premier, Richard Seddon, who had actively supported the act.
After two further years of private nursing in Wellington, Bagley took up a post in June 1908 as assistant inspector in the Department of Hospitals and Charitable Aid. Her role consisted largely of inspecting maternity hospitals. In particular she offered guidance to registered midwives who had not been formally trained. Most of her efforts focused on rural areas, starting with Southland and Otago, and she tried to impart to midwives the importance of strict hygiene in birthing practice long before the Department of Health's maternity campaign of the 1920s.
In 1911 Bagley was sent by the department to Ahipara in the far north where an outbreak of typhoid had occurred. This was part of a new initiative by the Department of Public Health to combat the high death rates from infectious diseases, particularly typhoid, among Māori. At Ahipara Bagley was to experience something which was, by her own account, 'quite out of the usual run of nursing', and not only because she was required to become an excellent horsewoman. Her patients were mostly children, and Bagley set up a temporary hospital at a local marae. She revealed a sensitivity which was only much later shown by hospitals in the cities: she allowed the parents of the children to come and sleep with them at night.
Following her success in setting up nursing stations at Te Karaka in Waikohu county and Te Araroa on the East Coast, Bagley was appointed supervisor of the native health nurses in January 1913 and was based at the District Health Office in Auckland. One of the first crises she had to deal with was the 1913 smallpox epidemic. This spread throughout the Auckland province, affecting approximately 1,800 Māori and killing 55. Bagley was dispatched to the north, 'almost liv[ing] in the saddle, riding from pā to pā', and helping with nursing, vaccination, quarantine regulations and disinfection. By 1914 she had 12 nurses working under her. In the following year Auckland's district health officer, Dr R. H. Makgill, paid a special tribute to her work in his annual report, pointing out that 'the establishment of eight or nine hospital camps during the year at short notice, and in more or less inaccessible places, is no small work'.
The First World War took Bagley away from normal duties for a time when she was appointed matron of the hospital ship Maheno in 1917, and subsequently of the Marama. In October 1918, three months after returning from overseas, she was called upon to assist with the influenza epidemic. Her primary duties involved organising voluntary nursing in Auckland city and suburbs. Her organisational skills were much appreciated in the crisis: within a few weeks almost 300 'lady volunteers' had passed through her hands.
Following the epidemic Bagley's attention returned to developing the rural nursing service. She laid the groundwork for what was to become from 1928 a specialist branch of nursing with its own postgraduate training course. After her retirement in 1930 it was reported that her 'visits were a source of encouragement and pleasure to the lonely nurses working among the Māoris'.
Apart from the very practical help Bagley offered the nurses, she was concerned about the future of the nursing profession itself. She was a regular contributor to the New Zealand nursing journal Kai Tiaki. In 1911 she ran a lecture course for the New Zealand Trained Nurses' Association, and was appointed a council member of the Auckland branch in 1913; six years later she joined the central council. In 1930 she convened a public health section of the Auckland branch.
Amelia Bagley died in Auckland on 30 January 1956 at the house in Royal Oak which she had built in 1923. She had played an important part in pioneering district nursing in New Zealand and in the professionalisation of the nursing service.