Fearing possible German occupation of New Guinea, Queensland annexed southern New Guinea but this act was repudiated by the British Government.

On the basis of this issue and a perceived French threat to annex the New Hebrides (Vanuatu), the Premier of Victoria James Service and the Premier of Queensland Sir Thomas McIlwraith began the first sustained campaign for a federal union.

They persuaded New South Wales to hold an Intercolonial Convention on External Affairs in Sydney in November and December 1883 where agreement was reached to form a Federal Council.

A Defence Report published in 1889 reflected that adequate defence of the continent would be impossible without combining the colonies’ forces.