On Saturday, the Omicron coronavirus strain expanded across Australia, putting efforts to reopen the economy to the test as a cluster in Sydney swelled to 13 cases and an infection was reported in Queensland.

The federal government is adhering to its strategy to reopen the economy in the hopes that the current strain is milder than earlier strains, but several state and territory administrations have moved to strengthen internal border restrictions.

On Friday, Australia announced its first community transmission of Omicron at a Sydney school. Authorities are looking into the source, and more instances are likely.

Queensland officials suspected their first Omicron case in an individual who had traveled from South Africa, and genome sequencing was underway.

“The public health unit ruled out Delta, but we haven’t been able to determine if it’s Omicron,” Health Minister Yvette D’Ath said. “However, it’s being treated as if it is.”

Arrivals from New South Wales, Victoria, and the capital territory will be tested, according to South Australian authorities on Saturday. For the first time in months, the state reopened its interior borders just a few days ago.

Several thousand people protested vaccination mandates in Melbourne, with the demonstrations now a weekly event that has been attracting groups of regular citizens, as well as far-right and conspiracy theory supporters.

A smaller counter-protest called to stop the far-right movement in the city and support vaccinations.

The state of Victoria, home to Melbourne, requires full vaccination to access most hospitality services and non-essential retail, as well as to work in health care and many other industries.

Nearly 88% of Australians over the age of 16 have been fully vaccinated, health data showed.

Anti-vaccination supporters number in single digits in Australia, according to polls. But unvaccinated patients make up the vast majority of those hospitalised with the coronavirus. In Victoria, 90% of the 44 people in the intensive care have not been fully vaccinated, health data showed.

Despite battling many outbreaks this year, leading to months of lockdown in Sydney and Melbourne – Australia’s largest cities – the country has had only about 834 confirmed COVID-19 cases and 7.9 deaths per 100,000 people, according to the World Health Organisation, a fraction of many other developed nations.

Australia has had just under 215,000 cases in total and 2,042 deaths.