Scott Morrison has warned international travel and border restrictions will remain in place for some time, arguing Australia must play it safe in the fight against coronavirus.
The prime minister has attracted criticism from business leaders, health officials and some colleagues for refusing to outline a framework for when the country will reopen.
The budget papers assume a mid-2022 deadline but there are no guarantees.
Mr Morrison warned Australia's relative safety from coronavirus could be compromised if borders reopen too early.
"It's called rushing to failure," he told 2GB radio on Wednesday.
"Australians are demonstrating a great deal of patience and the position we have been maintaining is the sensible one.
"That doesn't mean we're not planning for when we can do it ... but for now and for some time yet we need to play it safe because that's what protects lives and it's also what protects livelihoods."
The prime minister said Australia's relative success against coronavirus did not mean the country was somehow immune from the disease.
Singapore and Taiwan are both battling fresh waves of coronavirus infections despite extraordinary early success.
"The virus is quite an opponent," Mr Morrison said.
Rather than unlocking international travel, the prime minister wants people to focus on interstate borders, which he is not responsible for.
Mr Morrison has floated the prospect of vaccine passports, which could facilitate free movement across state borders.
Health Minister Greg Hunt has also suggested state premiers could waive lockdowns for people with vaccinations.
"That's something that we're supporting and encouraging and we'll work through that constructively with all of the states," Mr Hunt told reporters in Brisbane.
