A man and a woman, both in their 50s, are close contacts of previous cases in the Bondi cluster and have been in isolation.

NSW Health said the two, separate cases were reported overnight and will be included in tomorrow's numbers.

Investigations are under way into how they were exposed, with one line of inquiry that the man was infected at a Salvos store at Tempe.

Read more: Masks mandatory on public transport in Wollongong, Shellharbour

They are in addition to two new locally acquired cases reported in Sunday's numbers.

No shire venues visited by the two cases have yet been listed.

There are now nine cases linked to the Bondi cluster.

NSW Health has upgraded advice for anyone who was in Westfield Bondi Junction (including the car park) on June 12 and June 13.

Now, anyone who was in that location at any stage on those days must get tested for COVID-19.

Only people with symptoms and those in specific exposure venues at the listed times are asked to test and isolate.

People who do not have symptoms and have not been at the specific exposure venues at the listed times do not need to isolate, however everyone is strongly urged to avoid gatherings and minimise their movements, such as not attending the cinemas or trips to the ski fields. If you can work from home, please do so.

This broader surveillance testing will help NSW Health to determine the extent of potential transmission at Westfield Bondi Junction.

Detecting any cases early is critical to prevent ongoing transmission.

NSW Health continues to ask people to wear masks in indoor settings.

Masks are mandatory on public transport in Greater Sydney and the Blue Mountains and this is now being extended to include the Wollongong and Shellharbour council areas from 4pm today.

In addition, masks will become mandatory in all public indoor venues in the City of Sydney, Waverley, Randwick, Canada Bay, Inner West, Bayside, and Woollahra local government areas.

These venues include retail, theatres, aged care facilities and for front-of-house hospitality staff.

NSW Health continues to remind people to avoid non-essential visits to aged care and disability facilities, but if visiting, wear a mask and limit visits to two people per day.

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