The extension comes despite New South Wales recording no new local cases again overnight.
“Despite extensive investigations to date, NSW Health has not identified how the initial case, the man in his 50s, was exposed to COVID-19, which suggests he acquired the infection through brief contact with a currently unidentified person who was infectious in the community,” NSW Health wrote in a statement.
Restrictions around mandatory masks, a limit of 20 people gathering inside homes and visits to aged care facilities are now scheduled to end at 12.01am on Monday, May 17.
The extended rules apply across Greater Sydney, the Central Coast, the Illawarra and the Blue Mountains.
However, rules around mask use have been eased slightly, with masks no longer compulsory for customers shopping at retail stores.
Masks continue to be mandated for retail staff in public-facing roles.
There were six new cases of coronavirus found in the state’s quarantine hotels in the past 24 horus.
The results come from just over 18,000 tests – down from a high of over 22,000 the day before.