NSW to change COVID-19 case reporting 'for better comparison'

New South Premier Gladys Berejiklian has confirmed health authorities will change the COVID-19 reporting time frame.

Ms Berejiklian said today case numbers will be reported to 8pm every daily to enable comparisons with cases over the previous 24 hours.

Previously state officials had announced the total case numbers to 8pm each day, and then any additional cases diagnosed in the meantime.

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The premier said the change was being made "for simplicity's sake".

"For simplicity's sake, we will be reporting the numbers to 8pm every day, so that everybody can compare the 24 hours to the previous 24 hours," Ms Berejiklian said.

"But overnight and this morning the case numbers have been consistent with what we experienced yesterday."

Active cases are defined as people who have tested positive for COVID-19, are in isolation and are being clinically monitored by NSW Health.

A person will no longer be an active case when they are clinically released from isolation.

NSW today recorded 29 new cases of COVID-19 with Ms Berejiklian "putting everyone on notice" that a wider Sydney lockdown could be imposed this weekend.

Twenty nine locally acquired cases of COVID-19 were detected in the 24 hours to 8pm last night, 17 of which we already knew about. Twelve cases were previously unannounced.

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A crisis cabinet meeting will be held later today, to discuss how the Delta variant can be contained.

Ms Berejiklian said the reason for additional concern today was because exposure sites in Sydney had increased beyond the four LGAs currently in lockdown.