Australia will roll out a fourth dose of Covid-19 vaccines to its most vulnerable population starting next month, authorities said, as the country looks to limit fresh outbreaks ahead of winter.

The decision comes amid a steady rise in cases fuelled by the highly contagious BA.2 sub-variant of the Omicron strain and concerns of co-circulation of Covid-19 and flu viruses during colder months as most social distancing restrictions end, Reuters reports.

A second booster shot will be offered from April 4 to people who had their previous booster shot at least four months ago and are over 65 years, Indigenous Australians over 50, people with disability or severely immunocompromised, Health Minister Greg Hunt said during a media briefing.