A subcontractor worked at the Sydney Opera House for six days while potentially infected with Covid-19.
The iconic building was being deep cleaned on Wednesday morning after the subcontractor worked from July 1 to July 6 and then tested positive on Tuesday night.
Whether the worker was infectious for the entire time they were on-site is still unclear.
The opera house has been closed since June 26 in line with the city's 14-day lockdown.
A subcontractor worked at the Sydney Opera House for six days while potentially infected with Covid
'New South Wales Health is currently undertaking its investigations, and the Opera House is taking all necessary steps in line with its Covid Safety Plan,' a spokesman for the opera house said.
'In line with the current stay-at-home orders, the building has been closed to the public since Saturday June 26.'
Workers at the world-famous opera house are understood to have been classed as essential as they were preparing the venue for an upcoming performance, news.com.au reported.
New South Wales recorded 18 new Covid cases in the 24 hours to 8pm on Monday, with seven in the community for at least some of their infectious period, bringing the total number of people infected in the latest outbreak to 330.
A lone man walks past the Sydney Opera House during the city's strict lockdown on June 29. The opera house has been closed since June 26 in line with the city's stay-at-home restrictions
The figure was a significant drop from the 35 cases the previous day and Premier Gladys Berejkilian said the lockdown was having the desired effect.
The NSW government is expected though to extend restrictions until 11.59pm on July 16.
The harsh measures, originally brought in for a week on June 26, were enacted to confine the highly infectious Indian Delta strain to the epicentre in Sydney's east.
But the strategy has failed to keep locally-acquired cases under control across Sydney, with Tuesday's bringing the city's Bondi cluster to 225 cases - with over 100 more that are yet to be linked.
In another worrying statistic which prompted Ms Berejiklian to make her decision, 122 new cases were found to have been out in the community while infectious within the last ten days.