NSW Health is striving to achieve zero community transmission of COVID-19, while the premier announced a plan to get people out and about safely during summer.

Health authorities are NSW Health striving for zero community transmission of COVID-19 across NSW in the lead up to the school holidays with just one locally acquired case recorded in the latest reporting period.

There were four new COVID-19 cases reported from 7765 tests in the 24 hours to 8pm on Sunday including three returned travellers in hotel quarantine.

NSW Premier Gladys Berejiklian says a dip in the testing numbers is a concern.

"Complacency is our biggest concern and we just want people to make sure that they don't wait. If you feel the onset of the modest symptoms, please get tested," she told reporters on Monday.

"What has allowed us to conquer the spread of the virus to this point in time is high rates of testing. We know from the advice of experts disease is circulating, especially in western and south Sydney, and we need to make sure we keep testing rates high."

The premier warned NSW is going into a "high-risk period" with the easing of border restrictions with Victoria, and with school holidays just days away.

NSW Chief Medical Officer Kerry Chant said NSW was at a critical phase in the response to the pandemic.

"We are trying to identify any undetected chains of transmission in the community to drive it down towards no community transmission," she said.

"That will put us in the best position ahead of the school holidays where we know people will be out and about travelling across the state."

She said the state's one locally acquired case had already been isolating because they were a close contact of an infection linked to the Concord Hospital cluster.

"We are actually hopeful that we're really mopping up any remnants of disease transmission," Dr Chant said.

"It can mean that we can be confident we're approaching no community transmission, which is our goal."

The NSW government also announced a plan for residents to get out and about during summer in a COVID-safe way.

The plan encourages more outdoor dining and urges beachgoers to keep "a beach towel length" between themselves and anyone not from the same household, and to avoid peak times like the middle of the day.

Safe distancing will be marked out in parks and some public spaces from October and a COVID-safe summer program of events will be launched in outdoor areas.

Customer Services Minister Victor Dominello said COVID safety must be a priority during summer and urged people to not become complacent.

Meanwhile, NSW Health is still urgently attempting to contact anyone who took trips with a Silver Service taxi driver who tested positive on Saturday and worked in Sydney's west and southwest.

Anyone who was in his taxi between September 8 and 18 should monitor for symptoms.

NSW Health has identified a large number of people who rode with that driver, but nine passengers remain anonymous.

Dr Chant said some had hailed the taxi on the street, but many had booked online or used a credit card.

Health authorities will now work with the taxi industry on the possibility of using additional technology such as QR codes.