Thirty community cases of COVID-19 were recorded in Australia's New South Wales overnight, the state's health department said on Sunday.
In a statement, NSW Health said all the new cases were linked to the original cluster - which originated in the suburb of Bondi.
NSW's latest numbers come after Sydney and some surrounding areas entered a hard two-week COVID-19 lockdown on Saturday as authorities struggle to control a fast-spreading outbreak of the highly infectious Delta variant.
The health department said on Sunday that of the 30 new COVID-19 cases reported, only 11 were already in isolation during their infectious period.
"A further three cases were in isolation for part of their infectious periods," NSW Health said.
Under the rules in place for greater Sydney through July 9, people may leave home for essential work, medical care, education or shopping. The rest of the state will have limits on public gatherings and masks will be obligatory indoors.
New Zealand on Saturday night paused all quarantine-free travel with Australia until at least 11:59pm on Tuesday.