The first wave of Vietnamese displaced by the end of the war in their country had ended, and the later flotillas of asylum seekers had yet to begin.
Hawke's troubles lay instead with tens of thousands of overstayers who were swamping Australian resources and clogging the legal system.
Submissions to his Cabinet said there were at least 50,000 long-term illegal immigrants in Australia, with at least a further 30,000 joining them every year.
Existing detention centres in Perth, Melbourne and Sydney could hold only about 170 detainees.
Immigration and Administrative Services Ministers Chris Hurford and Tom Uren told the Cabinet that without a "balanced level of enforcement activity" the number of illegal immigrants could rapidly increase. They said "adequate custodial facilities" were essential.
The federal Human Rights Commission also recommended the establishment of new, purpose-built detention centres, rather than holding illegal immigrants and deportees in prisons.
The Cabinet agreed to build the centres to United Nations standards, and introduced mandatory detention.
Labor built centres at Port Hedland and the Curtin air force base near Derby, both in northern Western Australia.
Both were severely criticised by the UN and human rights groups, but were later joined by others at Woomera and Port Augusta, in South Australia, and offshore processing centres at Nauru and Manus Island in Papua New Guinea under former Liberal Prime Minister John Howard's Pacific Solution.
Labor later closed all centres except for small facilities in Sydney, Melbourne and Perth, but has since reopened Nauru and Manus Island, built a major centre on Christmas Island and opened another in Darwin.
The 1985 documents also show the pressure placed on the immigration system by overstayers, with the failure of policies introduced in 1981 to limit retrospective applications for permanent residence by illegal immigrants.
The system was clogged by 10,000 applications a year and an appeals backlog of about a year.
