The sudden death of the unvaccinated man in his southwest Sydney home will be referred to the NSW coroner.

The Daily Telegraph reported the man was a 27-year-old forklift driver Aude Alaskar, who collapsed in the Liverpool unit he shared with his wife on Tuesday and was unable to be revived by paramedics.

His death comes a year after that of a Victorian man in his 20s who was reported to be Australia's youngest COVID-19 fatality.

Premier Gladys Berejiklian said the man's death "demonstrates again how this disease is lethal, how it affects people of all ages".

Health Minister Brad Hazzard said the tragedy should prompt people 18 and over to consult their GP or pharmacist about whether to get the AstraZeneca vaccine.

"Go and get it," he said on Wednesday.

"Sadly we just heard one young person, in his 20s, has passed away which I think emphasises what we have been saying now for quite some time about two-thirds of all of our cases are currently under 40 years.

"It's a very serious issue."

Chief Health Officer Kerry Chant said the man had reached day 13 of his isolation period at his home after testing positive to the virus.

"He was being checked daily, and he did complain of feeling a little fatigued, but the deterioration happened suddenly," she said.

"With COVID you can get sudden deaths," she said.

His wife, who reportedly works in an aged care home, had also tested positive and was now being treated in hospital.

Last month a woman in her 50s also died at her western Sydney home where she was isolating after contracting the virus.

She was the mother of two Sydney removalists who allegedly continued driving to central west NSW after being notified they had tested positive.

A woman in her 80s also died in Royal Prince Alfred Hospital on Tuesday, bringing the death toll in the seven-week Sydney outbreak to 17.

Australian Associated Press