Australia is one of the slowest countries in the developed world to immunise its population against Covid-19 due to supply shortages, logistical problems and recent rising vaccine hesitancy.

With a population of 26 million, around 4.5 million doses have been administered according to government data.

With proof of vaccinations likely a requirement for international travel in the future, it may be a while before families in Ireland can be reunited with those close to them Down Under.

Australian Prime Minister Scott Morrison said recently that the country is likely to remain shut to visitors until late 2022.

The uncertainty makes it a tough and anxious time for those desperate to see old and new loved ones.

For Dubliners Maeve and Michael O'Connor, the couple haven’t been able to visit their two sons in Sydney for two years and meet new members of the family.

"It's so hard not being able to get over there and see them in Sydney. We haven't been able to get over for the last two years and now we've missed out on Patrick and he's only 10 weeks old," Maeve said.

Unsure of when they’ll be able to reunite, their son Stephen said the hardest part is their parents missing out on moments that they should be there to see.

"They can't meet Patrick and we haven't had that support when he's been a baby of being back to work and Kathryn's missed out on that support that she'd have," he said.

With the Covid-19 pandemic rumbling on, the massive Irish population in Australia is dealing with more than one illness.

"Homesickness here is like a disease at the moment," said Michelle O’Donnell, who is from Tipperary and living in Melbourne.

"Everyone is just so homesick, they just want to see their families. And with ageing parents… we have our child [and] we don't know if he'll meet his grandparents," she said.

It's a dilemma for many like Michelle who want to go home but are unsure about getting inoculated.

"I think the hesitation is just around the lack of information that can be provided to our age group in particular and the information pertaining to family planning. It's just that there's not a lot there," she said.

Australia's success in controlling the pandemic along with vaccine roll-out delays and concerns have cast a cloud over immunisation and future travel plans.

Vaccine hesitancy is on the rise and a recent survey suggested almost one-third of people living in Australia said they were unlikely to get a Covid jab.

A survey by the Sydney Morning Herald newspaper and Resolve Strategic found that those who had doubts were worried about side effects and felt like they did not have enough information about the vaccines. While a separate survey by the Australian National University (ANU) also found eight out of ten people were worried about possible side effects following concerns over rare blood clots from an AstraZeneca dose - the country’s main Covid jab.

Brónagh Ní Chuillin, who lives in Melbourne, told RTÉ News that she is prone to blood clots and is one of those worried about getting that vaccine.

"The government are after changing the goal posts where they are saying that they are not going to open the borders to 2022, I personally don't see why I should take the risk in taking the AstraZeneca vaccine," she added.

Australia, along with its neighbour New Zealand, has also been one of the most successful countries in the world to contain the pandemic.

Strong border controls, quarantine measures and snap lockdowns mean the level of community transmission has been low.

To much envy, life in Australia has been getting back to normal.

Professor Nicholas Biddle from the Centre for Social Research at ANU told RTÉ News that this success is reflected in people’s attitudes to immunisation.

"When we asked people about whether they were worried about getting infected, it was down to around 10% of the population. Those who weren't worried about getting infected were those who were far less likely to say that they would get vaccinated," he said.

Galway man Darren Ryan, who lives in Melbourne, is one of them.

He asked what incentive people would have to get a vaccine when the country is essentially Covid-free.

However a snap lockdown in Melbourne and a tempting trip home to Ireland in the near future might change his mind about getting vaccinated.

"If we have to travel and we want to travel down the road we're probably going to have to get it at some stage," he said.

Vaccine hesitancy is another stumbling block on Australia’s road to immunisation.

However, all these factors combined mean it may be some time yet before families can travel across the world to each other again.