The report’s author, economist Terry Rawnsley, said the departure of around 300,000 temporary visa holders from Australia this year may even "push Sydney’s population backwards" temporarily. Mr Rawnsley's report forecasts Sydney’s economy to shrink by between 6.8 per cent and 9.5 per cent in 2019-20. It will be the first time the city’s economy has registered an annual contraction since 1982-83. The economic slump will discourage some local couples from having children, further subduing population growth. Macquarie University demographer Professor Nick Parr said a temporary reduction in Sydney's birth rate is likely.

“Studies have found there tends to be a dip in the birth rate when economic conditions are uncertain,” he said. “Although it is more of a case that births are postponed until people’s living standards recover.” The strength of population growth during the next five years will depend on whether the economy recovers rapidly after a “V-shaped” recession or suffers a more prolonged downturn. In the event of a V-shaped recession the SGS Economics and Planning report forecasts Sydney’s population will be 100,000 lower by 2025 than expected prior to the epidemic. If the downturn is more prolonged the population is forecast to be 210,000 lower by 2025 than it would otherwise have been.

A Department of Planning, Industry and Environment spokesperson said the NSW government will seek advice from a range of experts to assess 2020 population trends and longer term population growth implications for NSW. "While overseas migration has halted, it is too early to tell what the impact of the coronavirus outbreak will be on both the Sydney and NSW population," the spokesperson said. Subdued population growth will take a toll on demand for new housing construction which is an important driver of economic growth. Last week the NSW Transport Minister Andrew Constance claimed a wave of transport projects would be part of a “silver bullet” to revive the NSW economy, financed in part by privatisation. But Mr Rawnsley said slower population growth, coupled with rising unemployment, would affect the cost-benefit equation for big projects due to roll out in coming years. That raises questions about the timetable for their construction.