Meanwhile, NSW has enjoyed its 18th consecutive day without a new locally acquired COVID-19 case but has boosted screening procedures for travellers arriving by air from Melbourne.

Avalon, on the northern beaches peninsula's northern tip, was the epicentre of the still-unsourced coronavirus cluster of 151 cases that emerged in the week before Christmas.

It prompted strict lockdowns during what would typically be the busiest trading period of the year, with the area divided into two zones north and south of the Narrabeen Bridge.

Stay-at-home orders in the southern part of the northern beaches lifted on January 2 and in the northern part of the region on January 9.

NSW Treasurer Dominic Perrottet announced on Thursday that small businesses in the area would be eligible for economic relief.

Businesses that experienced a 30 per cent decline in turnover during the Christmas period could claim a $3000 grant, while businesses that experienced a 50 per cent decline could claim $5000.

This would help the businesses cover unavoidable expenses such as rent and utilities.

Small businesses would be categorised as those involving sole traders or fewer than 20 full-time equivalent staff.

"The northern beaches community and businesses did an outstanding job in helping control the spread of the virus at a critical time and unfortunately that had a material impact on many businesses," Mr Perrottet said in a statement.

The "Dine and Discover" hospitality voucher program pilot on the northern beaches would also go ahead as scheduled.

Local businesses are able to sign up to join the program, which will give NSW residents four $25 vouchers to spend at hospitality and arts venues.

The program pilot is expected to begin this month.

The government also pledged to do more to promote the northern beaches as a destination for visitors and tourists, and to boost local mental health resources.

Business NSW said the financial assistance to the northern beaches was welcome.

"The northern beaches lockdown was especially difficult as it spread across the Christmas period, traditionally the busiest time for trade in that area," Business NSW chief executive Nola Watson said in a statement.

NSW recorded zero new local cases of COVID-19 in the 24 hours to 8pm on Wednesday, as well as three cases in travellers in hotel quarantine. The tally came from 10,551 tests.

NSW Health said in a statement it would begin screening passengers arriving on flights from Melbourne after a COVID-19 hotel quarantine leak in the city.

A hotel quarantine worker in Melbourne and two of his family contacts have come down with COVID-19.

"Passengers will be screened for symptoms of COVID-19 and asked if they have been to any of the venues of concern listed by the Victorian Department of Health and Human Services," NSW Health's Jeremy McAnulty said.

"These Melbourne cases are a timely reminder that COVID-19 can emerge at any time."

Five people in NSW have also been sent into self-isolation for 14 days after they spent their recent hotel quarantine stint in a separate Victorian facility where guests in adjacent rooms infected each other.

Premier Gladys Berejiklian said on Wednesday the four-square-metre rule for NSW venues would be eased to two square metres from February 12 if no virus outbreaks occurred in the meantime.

Meanwhile, a function venue in western Sydney's Fairfield Heights has been fined $11,000 after being caught without a COVID-safe plan or functioning CCTV cameras.

Australian Associated Press