New South Wales (NSW), Australia's most populous state, reported the highest spike in new locally obtained Covid-19 cases in over a week on Tuesday (June 22), raising the likelihood of tougher restrictions in the country's largest city, Sydney.

On Tuesday, officials in NSW revealed ten new locally acquired cases as they battle to contain a new cluster of the highly infectious Delta virus type.

Seven cases were recorded after the 8 p.m. deadline on Tuesday, and they will be included in Wednesday's figures. Six of the seven infections are spread by the home contacts of previously isolated individuals.

Authorities have linked a driver who transports abroad airline staff members to the latest outbreak, which has expanded to 21 cases in six days and is the first in the state in more than a month.

The NSW government made masks essential in Sydney's buses, trains, and ferries for five days in an effort to contain the outbreak, while advising the city's 5 million people to use masks indoors.

With slightly over 30,350 cases and 910 deaths, Australia's Covid-19 numbers have remained reasonably low thanks to quick tracing systems, strict social distancing restrictions, and strong community compliance. This year, it has reported zero local instances on most days.