Following the withdrawal of the British garrison in 1870, the colonies slowly came to the realisation that defence was not a matter of individual effort. To be effective, it needed co-ordination at the national level. In 1877, at the insistence of New South Wales, Major General Sir William Jervois (who later became Governor of South Australia) and Lieutenant Colonel Peter Scratchley RE were made available to advise the colonies on defence matters. A succession of inter-colonial conferences, to consider the defence of Australia, were held from the early 1880s. These initiatives clearly illustrate the importance of the defence debate as a factor in the overall impetus for federation.²¹

While a gradual process, training and efficiency of the colonial forces did improve. The introduction of higher defence structures, and the posting of British officers and warrant officers to appointments in these higher headquarters, as well as into units, introduced an air of reality into colonial defences and did much to improve the efficiency of colonial regiments.

While the colonies believed the Torres Strait, New Guinea and King George's Sound were an Imperial responsibility, they also recognised their strategic importance. A small detachment of Royal Marines was stationed at Port Albany, on Cape York, between 1865 and 1867. After their withdrawal, Queensland maintained a tenuous presence there, although it was realised that Thursday Island would be a better location.

The threat of German annexation of New Guinea led Queensland, supported by the other colonies, to annex New Guinea in April 1883, much to the astonished consternation of the British Government which was firmly opposed to further colonial expansion. Resolute action by the colonies finally secured a British Protectorate over southern New Guinea (Papua) in October 1884. Much to colonial chagrin, an astute Germany annexed the northern portion two weeks later.²²

In 1887, the defences of Thursday Island and King George's Sound were discussed at a London conference. By 1893, both areas had been fortified and garrisoned.

Meanwhile, railway communications within Australia had developed to the stage where, in spite of different gauges, it was possible to transfer troops rapidly from one colony to another, except Western Australia and, of course, Tasmania. In 1889, Major General Brian Edwards, who had recently completed a survey of colonial military forces, noted that it would be possible to mobilise on a standard brigade basis. In his view, this would 'prevent the unseemly scares which take place (in Australia), whenever the relations of the mother country with a foreign power are somewhat strained'. He further believed purely volunteer units were unsatisfactory - judging paid or partly paid forces ideal for Australia's needs. While neither Britain nor Australia did not fully endorse his views, his concept of mobile rather than static defence, based on coastal forts, gradually came to be accepted.²³