Health authorities are worried catch-ups with colleagues and friends during December could end up being super-spreader events.
Already in New South Wales, hospitality venues and parties are emerging as major outbreak sites, with 84 cases linked to a Newcastle nightclub.
Thousands of people have been sent into isolation ahead of Christmas.
People who are eligible for their booster shot are being urged to get it as soon as possible.
Authorities have also warned that New South Wales, one of the states where the Omicron variant has emerged, is at risk of returning to 1000 daily cases.
While health authorities have suggested that early data indicated Omicron is a less severe Covid variant, it appears to spread very quickly.
Another factor will be the final removal of COVID-19 restrictions from tomorrow, with unvaccinated people set to receive the same freedoms as the vaccinated.
From tomorrow, COVID-19 safety plans will be optional for businesses, and density limits in all settings will be removed.
QR check-ins will only be required for hospitals, aged and disability care facilities, gyms, places of worship, funerals or memorial services, personal services, pubs, small bars and registered clubs, nightclubs, strip clubs, sex on premises, and indoor music festivals with over 1000 people.
Masks will only be required on public transport, planes, in airports, and for front-of-house hospitality staff who are not fully vaccinated.
Unvaccinated people will also be allowed in pubs, hospitality venues, non-essential shops, and to travel between Sydney and regional NSW.