Limiting Immigration
In the early-1990s, Australia had a migration rate of more than 35,000 pax per year. The average for the 20th century was 52,000 per year. This level of immigration would still mean Australia receives more immigrants than other developed countries. These numbers would allow Australia’s population to stabilize eventually, but they would add several more millions of people before reaching our peak.
Once population growth has ended, either migration could be increased gradually to maintain a stable population, or the population could be allowed to decline to a lower and more sustainable level.
Unlike the US, Australia did not want to become a huge manufacturing country and experience a flood of immigration. So once Australia became a developed country, the Australian government made immigration extremely tough. During the 20th century Australia strictly enforced the White Australia policy up until the 1970s, making it difficult for immigrants from any non-white countries to immigrate. Slowly Australia changed that immigrants are given visas based on the job they are applying for. It is basically impossible for an unskilled migrant to immigrate unless they marry an Australian citizen.