Separated friends and families are now able to reunite without the need to quarantine for 14 days, after WA ended its hard and long border restrictions with NSW and Victoria on Tuesday.
It comes after NSW reported its fourth consecutive day of no local COVID-19 transmission in the 24 hours to 8pm on Monday night.
Six cases were reported in returned overseas travellers among the 6040 tests undertaken in the time frame.
But NSW Health said there weren't enough people getting tested.
"With restrictions being eased and borders reopening, now is not the time to be complacent," it said in a statement.
"Anyone with even mild symptoms should get tested on the day they get symptoms, otherwise we will miss cases.
"Don't wait to see if your runny nose or sore throat goes away."
Meanwhile, investigations continue into the source of last week's COVID-19 infection in a Sydney quarantine hotel cleaner.
The strain of the virus appears to be of US origin and "work is progressing in examining potential links to international aircrew who were self-isolating in the hotel at the time".
Close contacts of the cleaner were tested and no further positive results have been identified.
NSW Health also provided updated advice to people who travelled between November 27 and 30 on the same Minto to Sydney train and light rail services as the infected cleaner.
People who travelled on the same services and may have been in the same train carriage are considered close contacts.
They were previously advised to get tested immediately and self-isolate until further notice. These people are now advised to self-isolate for a full 14 days since the last date of travel and get tested at a COVID-19 clinic.
People who travelled on the same services and know they were not in the same carriage as the cleaner should get tested and self-isolate until a negative test result is received.