Australia on Friday pressed over-50s to get their coronavirus shots, as fears mounted that vaccine hesitancy could be priming the country for disaster.

Australia is one of the few countries in the world to eliminate community transmission of Covid-19, but vaccine rollout has been slow.

After chronic delivery delays, there is growing evidence that older Australians are more concerned about the AstraZeneca vaccine's side effects than catching the virus.

‘I encourage those over 50 to get the jab,’ Prime Minister Scott Morrison said Friday, ‘and if you are over 70, I would very much encourage you to.’

‘My mother has had it, my mother-in-law has had it, and they are doing great,’ Morrison added, trying to ease concerns about widely publicised risks of blood clotting.

The World Health Organization recommends continued use of the AstraZeneca shot, arguing that the benefits far outweigh the associated rare risk of clots.

But according to a recent poll by Essential Report, only 42 percent of Australians say they would get vaccinated as soon as possible, and almost a third would get the Pfizer shot but not AstraZeneca.

The poll showed a notable jump in vaccine hesitancy among over-55s since early April, when the government said under-50s would get the Pfizer rather than AstraZeneca jabs.

A separate Resolve Strategic poll for the Sydney Morning Herald showed similar results.

An estimated 25 percent of the 4.6 million vaccine doses distributed across Australia so far have not been used.

Peter Doherty, who won the Nobel Prize for medicine in 1996, weighed in Friday, tweeting: ‘I'll be getting my second shot of the AstraZeneca vaccine.’

Blood clots are ‘certainly a risk we could do without’, he said.

‘But one fatality with more than a million doses beats the 5-10,000 deaths (+ much, much more chronic illness) per million we might expect if the virus cut loose here.’

- 'We're dawdling' –

Experts say Australia's runaway success in eliminating Covid-19 could be leading to complacency.

They point to Taiwan as evidence that a stellar record of combating the virus can quickly be lost.

The island with a population of 24 million -- similar to Australia's 25 million -- has recorded well over 1,000 new infections in five days.

Australia bet heavily on the AstraZeneca jab after efforts to produce a local vaccine failed.

It has since increased orders for the Pfizer and Moderna vaccines, which are based on a different mRNA technology.

The government's critics say the slow rate of vaccination means Australia's borders, which slammed shut in March 2020, will have to stay closed long into next year.

‘We're dawdling,’ said opposition labour member of parliament Andrew Leigh.

‘The health minister should be encouraging everyone to get vaccinated as soon as possible.’