Australian Grand Prix organisers will need to know by September if the Formula One race can go ahead, or the Melbourne event will be cancelled for the second straight year.
This year's GP is slated to be held from November 18-21, away from its traditional March timeslot due to COVID-19 complexities.
But the federal government's prediction in last week's budget of international borders remaining closed until mid-2022 was a worrying development.
AGP corporation boss Andrew Westacott admitted there was a lot of work to do with the governments, health departments and F1.
"It's complex to deliver a grand prix in normal years, let alone in a year where we're coming off cancellations and COVID does exist," Westacott told SEN.
"The current date we're looking at is around the 13th or 17th of September from a build commencement point of view.
"We've still got time to work through those details but clearly come September we would wanting to be building because you can't delay the build for something as important as a grand prix circuit that needs a lot of safety requirements."
The GP was the first major sporting event in Australia to be canned last year at the start of the COVID-19 pandemic.
In one of Australian sport's most dramatic days, F1 fans were left waiting outside gates unaware the event had been cancelled after a McLaren crew member tested positive to coronavirus.
Westacott's comments come after an ABC report on Monday detailed this year's GP and the 2022 Australian Open were at risk because of the border situation.
Tennis Australia chief executive Craig Tiley remains optimistic the grand slam will go ahead as planned at Melbourne Park and will not need to be shifted overseas.
Prime Minister Scott Morrison said it was "premature" to be making decisions on those events.
"I would note, though, it's very different coming to Australia, because in most of the countries they're moving around in, COVID is riddled through those countries," he told reporters on Tuesday.
"Australia is not riddled with COVID. So the risk profile in other countries is very different.
"That is something that we certainly want to protect."
