On Sunday, Dan Tehan, the Minister for Trade, Tourism and Investment, confirmed that the travel bubble, which will allow quarantine-free travel between the two countries for the first time since March 2020, has been delayed as a result of Australia's interrupted vaccine rollout and the Covid-19 outbreak in Sydney, Xinhua news agency.

The scheme was set to open in July or August.

"When it comes to when we were looking at a bubble, it has been put back due to the third wave of the virus," Tehan told Nine Entertainment newspapers.

"It's very difficult to put a time frame on it but when you look at the plan that Singapore has put in place, and you put it alongside the plan that the prime minister has announced, the hope might be towards the end of the year that you could look at a travel bubble with Singapore."

More than one third of Singaporean adults have been fully vaccinated against Covid-19 compared to just 10 per cent of Australians.

Tehan flagged that vaccine passports would become a reality for years when Australians are again allowed to leave the country freely.

"If we are able to open up next year, you would expect that you're probably looking at 12 months or two years where this is going to be part of what you're doing, it could be like the little yellow booklet for yellow fever," he said.