Up to 50 people will be able to gather outdoors and in backyards in NSW from Tuesday as the state hits 18 straight days without a local COVID-19 case.

Big backyard Christmas barbecues are back on the cards after the NSW government eased a slew of COVID-19 restrictions.

Up to 50 people can convene outdoors - including in backyards - from Tuesday across NSW, while 30 people can gather indoors.

All NSW venues up to 200 square metres in size, including hospitality venues, will also be able to host one patron per two square metres.

"We do appreciate this has a risk and we appreciate also that at social events and private homes, social distancing is difficult to maintain," NSW Premier Gladys Berejiklian told reporters on Wednesday.

"But we ask everybody to be very COVID-safe, especially if you have vulnerable people as part of your family or social gathering."

Additionally, NSW public health orders requiring employers to allow staff to work from home will end on December 14, with the government keen to get workers back into Sydney's CBD.

This prompted a renewed plea from Ms Berejiklian and Transport Minister Andrew Constance for people to wear masks on public transport as patronage increases.

"Private companies and organisations can make decisions about what they do with their employees into the new year," Ms Berejiklian said.

"We don't want to go down the mandatory path, we want to ask people to get better at wearing masks on public transport ... although community transmission is zero, we need to wear masks, just in case."

It comes as NSW records its 18th consecutive day of zero locally acquired COVID-19 cases in the 24 hours to 8pm on Tuesday, while four cases were uncovered in returned travellers in hotel quarantine.

The tally came from almost 16,300 tests.

The changed gathering restrictions in NSW will coincide with the reopening of the NSW-Queensland border on Tuesday, in time for summer. Access to Queensland for Victorians will resume on the same date.

Qantas and Jetstar plan to operate an additional 1200 return flights to Queensland from NSW and Victoria in the lead-up to Christmas.

Virgin Australia also says Queensland's decision to reopen the border will help the airline and tourism industry to get back on its feet.

Ms Berejiklian was chuffed by the development.

"We feel that planning is absolutely necessary to ensure that we keep our economy moving, we keep jobs going, and that people feel more confident in 2021 about their livelihoods and their jobs," Ms Berejiklian said.

Peak NSW business lobby group Business NSW said the eased restrictions from next week constituted a "clear pathway" to recovery.

The lobby group was pleased by the suspension of work-from-home orders.

"This has been the cause of great frustration from businesses of all sizes right across the state," Business NSW chief executive Nola Watson said in a statement.

"This means businesses can properly plan and execute an integrated return to the office program for their employees, while ensuring a safe and compliant working environment."

The NSW Tourism Industry Council welcomed the easing of indoor physical distancing restrictions in time for the summer holiday season.

The move would allow people to take advantage of the budget's 'Dine and Discover' scheme that entitles every NSW adult to four $25 vouchers to spend at COVID-safe dining, arts and tourism businesses.

Meanwhile, NSW Health has discovered COVID-19 virus fragments in sewage at the Liverpool sewage treatment plant in western Sydney, prompting renewed calls for local residents to get tested.