Following this week's massive surge in COVID-19 cases - attributed mainly to the high transmissibility of the Omicron variant following the easing of border restrictions - businesses may be looking at massive staffing shortages all over again.

It's not just the thousands of cases that were recorded nationally since Monday, or the Doherty Institute's predictions that daily cases could hit 200,000 around the end of January. It's also the thousands of close contacts that are being recorded around the actual cases, and the isolation rules that are putting workers out of action for seven days at a time until they pass two PCR tests.

ABC News highlights one estimate by University of Sydney top epidemiologist Professor Alexandra Martiniuk suggesting that on Thursday alone, there might have been between 23,000 to 80,000 close contacts, all of whom would not be allowed to return to the workplace for a week. Professor Martiniuk also predicts that with the sheer number of workers required to isolate, crucial industries - such as food, transportation, emergency responders, even sewerage, those where the notion of working from home is laughable - may end up short-handed. And that's a whole different, worse, problem from retailers' festive season woes.

"Even if Omicron was so mild it caused zero hospitalisations, the disruption to our society and health system in terms of workers isolating is massive, especially in crucial workplaces such as food, healthcare and transportation," ABC quotes her saying.

The COVID surge and the prospect of an enormous nationwide staff shortage comes at a time when border easing and economic recovery has led to more jobs being posted, and also as companies consider taking a harder stance - up to a third looking at a 'no jab, no job' policy.

On top of this, the government has been sending mixed signals about safety measures. Prime Minister Scott Morrison refuses to be heavy-handed with health and safety mandates but also suggested he might be open to mandatory indoor masking, even as the technical advisory group on immunisation looks at accelerating vaccination programmes and including booster shots in the definition of 'vaccinated'.