The disturbing Covid number which has authorities scrambling

Four weeks on from discovering the northern beaches outbreak, NSW Health is still trying to link 14 recent coronavirus cases to known clusters.

Five locally-acquired coronavirus cases were reported on Tuesday from just under 15,000 tests.

The origins of two new cases - one on the northern beaches and one in Blacktown - are so far unknown.

All up, 12 cases found since December 16 are still being investigated by NSW contact tracers, including three detected before Christmas.

People relax on NSW beach.
An alarming number of Covid cases have yet to be linked to known clusters. Source: AAP

A further two cases - from the Canterbury-Bankstown and Lane Cove council areas - have been fully investigated without any link found.

NSW Premier Gladys Berejiklian says it is unlikely any restrictions in Greater Sydney will be eased this week.

"We're still seeing community transmission," she said on Tuesday.

"Even though in most instances, (they are) household contacts or people already in isolation, but we have had a couple of examples where they're still unlinked, and that's always a concern."

Premier vows not to give up in search for patient zero

She again backed the contact tracing teams, saying their work allowed her government to make decisions that didn't place "unnecessary burdens" on residents.

"We have the best health contact tracing team in the nation," Ms Berejiklian said.

She said the search to identify the case that sparked the northern beaches outbreak wouldn't be stopped.

"We never give up the hunt in NSW," she said.

"Sometimes it might take us hours, sometimes days, or sometimes weeks, but we always get to the bottom of what we think happened, and I'm confident we'll get there.

"But we also have to give our experts time to make those connections."

Pemier Gladys Berejiklian.
The unknown cases means premier Gladys Berejiklian is unlikely to change NSW restrictions any time soon. Source: AAP

Officials concerned by low testing numbers

Testing numbers reported on Tuesday were again below that of the day before, concerning officials.

Daily testing figures fell as low as 6173 just before the Northern Beaches outbreak was discovered.

"We need 25,000-plus tests a day and we particularly need to see testing in places such as the Northern Beaches, such as western Sydney where we've seen cases recently," NSW Health's Jeremy McAnulty said on Tuesday.

NSW has more than 200 active coronavirus cases, including one person who is in hospital in intensive care.

Alerts remain out for dozens of hotspots, including a shopping centre in Warriewood, a post office in Hurlstone Park and a workers club in Blacktown.

Meanwhile, the ACT and Northern Territory have lifted travel restrictions for the Central Coast, Wollongong and some parts of Greater Sydney.

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