The Australian state of Victoria was ordered into a five-day lockdown on Thursday following a spike in Covid-19 infections, joining Sydney as the country's two main population hubs battle an outbreak of the highly contagious Delta variant.

From midnight, the state of 6.6 million people was told to stay home except for grocery shopping, essential work, exercise, healthcare and getting vaccinated. The lockdown in Australia's second-largest city of Melbourne is its fifth since the pandemic began a year and a half ago.

Combined with a stay-home order already in force in Sydney, the measure means nearly half Australia's 25 million population is under lockdown.