Australian Prime Minister Scott Morrison has ruled out introducing new laws that would allow employers to mandate Covid-19 vaccines.

Morrison said on Friday that employers may wish to enforce a "reasonable directive" that staff must be vaccinated against Covid-19 but that it must be "consistent with the law", Xinhua news agency reported.

It came after a meeting of the National Cabinet during which the government's top law adviser, the solicitor-general, briefed the prime minister and state and territory leaders on legal issues surrounding mandatory vaccinations.

Morrison said that there were some situations where employers could mandate vaccines but that the government would not introduce laws for wider mandates.

As of Friday about half of the Australian population was in lockdown in three states to prevent the spread of Delta variant of Covid-19.

The state of Victoria and some regional areas of the state of New South Wales (NSW) are the latest ones joining the ongoing lockdown gripping both the Greater Sydney and its surrounding areas, as well as part of the state of Queensland.