Australian universities could lose up to US$11 billion dollars as an indefinite coronavirus border closure locks out the foreign students who keep the sector afloat, the industry said Wednesday.

Lobby group Universities Australia said the revenue shortfall would have a lasting impact on not only higher education staffing and facilities but also undermine the sector's world-class research and innovation.

Education is Australia's third-largest export -- behind only iron ore and coal -- with more than 500,000 international students enrolled last year, bringing about Aus$32 billion (US$22 billion) into the economy. Universities Australia said its modelling showed the sector could expect coronavirus-linked revenue losses of up to Aus$4.8 billion in 2020, growing to Aus$16 billion through to 2023.

"Not only does that revenue support the staff and facilities to educate the next generation of skilled workers, it also pays for much of the research and innovation that keeps Australia internationally competitive," the group's CEO Catriona Jackson said.

Universities are pushing hard for a cash injection after being ruled ineligible for government wage subsidies during the pandemic, putting more than 20,000 academic and support staff jobs at risk. Australia's schools were almost halfway through their first semester when Prime Minister Scott Morrison controversially told struggling international students to "go home" on April 3 as the country began locking down businesses to curb the spread of COVID-19.

Many students remain stranded in the country and are relying on charities for food handouts after they were excluded from government support packages designed to cushion the economic hit from the epidemic. Morrison has said the ban on foreign travellers will likely continue for months, although some states are considering exemptions for foreign students willing to undergo a mandatory 14-day quarantine on arrival.

Australia was also one of the first countries to close its doors to Chinese citizens in the early stages of the coronavirus outbreak, shutting off the country's largest source of international students. The university sector's dependence on Chinese students has sparked a string of other controversies, including clashes between pro- and anti-Beijing students on campuses in 2019 and the suspension of a high-profile Chinese Communist Party critic by the University of Queensland last week.