Australia's Queensland state has reported 16 locally acquired Covid-19 cases as authorities warn that a lockdown in state capital Brisbane might be extended beyond Sunday if people flout the tough restrictions, reports Reuters.

It is the same number of cases as detected the previous day (Tuesday), and seven are linked to three schools.

Infections from the highly infectious Delta variant have plunged southeast Queensland, which includes Brisbane and some neighbouring regions, into a lockdown as officials rush to douse the outbreak, the biggest in more than a year.

State Deputy Premier Steven Miles has implored residents to avoid all non-essential shopping and remain home.