There are 16 contacts who have been identified in New Zealand as being at locations of interest in Sydney.
Speaking in Sydney on Tuesday morning, Premier Gladys Berejiklian said the requirement to wear face masks in public indoor areas and on public transport, which was slated to end at midnight Wednesday, will be extended another seven days.
There are no new cases of Covid-19 in the community today, the Ministry of Health reported in a statement.
"We will extend it to all of Greater Sydney... excluding the Central Coast and the Hunter", she said.
"The NSW Government will be extending the existing mask-wearing provisions for an additional week", the Premier said.
The three new cases included in Tuesday's numbers include a woman in her 60s from the Illawarra, a woman in her 40s from Sydney's northern suburbs, and a woman in her 20s from the eastern suburbs who is believed to have contracted the virus through "fleeting contact" while working at Westfield Bondi Junction.
The first two cases, revealed yesterday and counted in today's tally, are close known contacts of existing cases. Residents of Sydney's eastern suburbs and Wollongong have been asked to be "especially vigilant".
The Government is set to announce if there are any new cases of the virus in the community and in managed isolation.
The suspension will initially be in place for 72 hours while the source of new infections is investigated.
Other Australian states are implementing restrictions on visitors from NSW or banning visitors from exposure sites, after the "Bondi cluster" roses to 21 cases.
"I urge parents to wait for instructions from the school because we are keen to make sure that students and parents have access to testing and we want to make sure there isn't a rush with all parents descending on the school at the same time".
"We anticipate in coming days ... those in isolation with a household contact are likely to develop the disease given how contagious it is".
Public transmission remains an area of high concern.
Previously, anyone who was in the complex, including the vehicle park, on 12 or 13 June was told to get tested, but now anyone who was there from 14 to 18 June must also be swabbed.
NSW Health said 28,645 coronavirus tests were carried out over the past 24 hours, and 18,045 vaccine doses were administered.