Australians have reacted with outrage at the release of a confronting new advertisement warning about the dangers of Covid-19.

The government is set to roll out the shocking 30-second clip, which shows a terrified young woman struggling to breathe on a ventilator, on free-to-air television across the nation from Sunday night.

A preview of the ad immediately attracted a public backlash, with many taking to social media to call for it to be ditched.

It comes as health experts push for harsher lockdown restrictions to avoid the further spread of Covid-19 after NSW recorded 77 new cases on Sunday, and one death.

Adjunct Professor at UNSW and strategic health policy consultant Bill Bowtell took to Twitter to call for the ad to be cut.

"This ad should be immediately taken off air," Bowtell tweeted.

"Today in Sydney a young girl with Covid – about the same age as the actor in the ad – is on a ventilator fighting for her life.

"This insensitive ad can only distress her family and friends. It is misconceived in every way."

ICU specialist Tom Solano also criticised the dramatic vision, which shows pure fear in the young woman's eyes as she looks at the camera while unable to breathe properly, as inaccurate.

"As an ICU specialist please know that we'd never deliberately let you suffer like that. We'd try to get increased support before it got that bad," he said.

Others joined in a chorus of outrage at the ad, with some pointing out the irony of the scene, showing a young Australian in distress from a virus she likely cannot be vaccinated against yet.

Another Twitter user wrote: "Gotta keep everyone scared".

However, there are some Australians who are supportive of the ad, saying it's a good "wake-up call".

Another wrote: "Graphic indeed, but people need to be jolted out of the vaccine hesitancy!"

That's exactly what the government is hoping to achieve by airing the ad, with Australia's chief medical officer Professor Paul Kelly saying its purpose is to shock us and grab our attention.

"There will be a new advertisement running from the Australian government tonight. It is quite graphic. We are only doing this because of the situation in Sydney. And it will be running in Sydney."

With the outcry continuing to grow on social media, a government spokesperson issued a statement defending the ad, insisting it is necessary to boost vaccination numbers in the community.

"The Delta variant is much more infectious and is impacting younger cohorts more than previous variants," the spokesperson said.

"The clip encourages people in NSW to book their vaccination, but also to highlight the need to stay home and get tested.

"As of this morning – there are currently 52 Covid-19 cases admitted to hospital, with 15 people in intensive care, five of whom require ventilation. Seven of the 15 cases in ICU are under 55 including one person in their teens, one person in their 20s, one in their 30s, one in their 40s, three in their 50s.

"People who work in industries like aged care and health care, and people with health difficulties, can all book to get their vaccination right now no matter their age.

"More than 9 million doses have been administered in Australia, and anyone 18 years and older can speak to the GP about getting access to an AstraZeneca vaccine."

"It's meant to be graphic, it's meant to push that message home."

The ad campaign is part of the government's push towards vaccinating the public, with this specific clip attempting to prove to the public how anybody can be affected by a particularly nasty case of the virus.