The coronavirus-induced border closures and lockdowns in Australia will have an enduring impact on government coffers and population growth, according to official forecasts released on Monday, Reuters reported.

The Australian government's "Intergenerational Report 2021" forecasts the budget will remain in deficit for at least another 40 years.

"The economic crisis associated with the COVID-19 pandemic has placed significant demands on public finances in Australia and around the world," the report said. "While Australia's stronger-than-expected economic recovery has flowed through into the fiscal position, the effects of the pandemic on the budget are expected to remain into the long term."

"The economic recovery is well underway, but some effects from the pandemic will persist," the report adds.

Australia now expects its population to total 38.8 million by 2061, down from its last forecast in 2015 when it saw it hitting 40 million by 2056. Its population currently stands at 26 million.

"This is the first time there has been a downward revision of the long-term population projections in an intergenerational report," Treasurer Josh Frydenberg said in his speech. "This means the economy will be smaller and Australia's population will be older than it otherwise would have been, with flow-on implications for our economic and fiscal outcomes."

Responding to questions following his speech, Frydenberg reiterated Australia would only open its international borders if it is safe to do so, suggesting no urgency to bring in overseas visitors and migrants.