NSW Chief Medical Officer Kerry Chant says the festive season will bring new challenges in controlling the spread of COVID-19 as people relax and party.
NSW Health says anyone who attended the following four venues is considered a casual contact and must monitor for symptoms and get tested immediately if these develop:
As COVID-19 restrictions ease in NSW, authorities remain anxious about low testing rates, undetected cases in the community and people dropping their guard as the festive season approaches.
"This is now a critical period," Chief Medical Officer Kerry Chant said on Wednesday.
"We know that if this virus gets a foothold in the community it can go off like a wildfire, particularly as we ease restrictions, particularly if we drop our guard in terms of those COVID-safe practices.
"As we go into Christmas, we know that people are going to be welcoming people into their homes ... and household celebrations (and that will) present challenges for COVID transmission."
Dr Chant said authorities were still dealing with three COVID clusters in southwest Sydney and although case numbers were low it was vital more people got tested as the festive season began.
NSW Health had detected traces of COVID-19 in sewage in Sydney's southwest, indicating it remained a hotspot with undetected cases and the community needed to be on alert for symptoms and get tested.
There are guidelines on the NSW Health website on how to participate safely in Halloween on Saturday, including using wrapped lollies, mask-wearing and maintaining social distancing.
"And please don't trick or treat if you're unwell - you should be down getting a COVID test," Dr Chant said.
There was one new case of locally acquired COVID-19 in NSW and seven cases detected in returned travellers in hotel quarantine in the 14,382 tests in the 24 hours until 8pm on Tuesday.
The new local case was a household contact of another case in southwest Sydney who had been isolating before being diagnosed.
Despite low case numbers, Premier Gladys Berejiklian urged people not to become complacent, saying authorities remained concerned about the festive season ahead.
"We want to make sure we get on top of this before we get into a season where people are more mobile and obviously in closer contact with each other," she said.
"It's really difficult not to let your guard down because it's easy to think that we're immune and the case numbers are low ... (but) the virus is as contagious as ever, as dangerous as ever and it remains undetected in the community," she said.
She urged all businesses to get the QR code to electronically track any visitors to their venue ahead of the Christmas season.
She also welcomed the Tasmanian government's decision to open its borders to people from NSW from 6 November and said she hoped Queensland did likewise in an announcement expected on Friday.
"I also urge the WA government to do likewise because there is no reason why NSW residents shouldn't be welcomed to other states," she said.
Ms Berejiklian said she'd be monitoring how Victoria goes controlling the spread of COVID-19 over the next two weeks as it emerges from lockdown, before she considers opening the border.
"We're going to keep a close eye on that and if we see that within a couple of weeks of those restrictions being eased the virus is still under control, then we'll have no issue with taking the border down," she said.
"We don't want the border there for a day longer than it needs to be but we also need to be sensible.
People in Australia must stay at least 1.5 metres away from others. Check your jurisdiction's restrictions on gathering limits. If you are experiencing cold or flu symptoms, stay home and arrange a test by calling your doctor or contact the Coronavirus Health Information Hotline on 1800 020 080.
News and information is available in 63 languages at sbs.com.au/coronavirus.