The Australian city of Sydney has ordered a shutdown of building sites, banned non-essential retail and threatened fines for employers who make staff come into the office as new Covid-19 cases kept rising three weeks into a citywide lockdown.

Authorities in New South Wales state, of which Sydney is the capital, also banned hundreds of thousands of people in the city's western suburbs — the worst affected area — from leaving their immediate neighbourhoods for work, as they recorded 111 new cases in the prior 24 hours, up from 97 the day before.

The state also recorded an additional death from the virus, taking the total to three since the start of the year and the national total to 913 since the pandemic began, according to a Reuters report.

“I can't remember a time when our state has been challenged to such an extent,” NSW Premier Gladys Berejiklian told a televised news conference.