Australia's second-largest city will exit its coronavirus lockdown in late October if vaccine targets are met under an official roadmap released today.

About five million people in Melbourne have been under stay-at-home orders since 5 August, the sixth lockdown they have endured so far during the Covid-19 pandemic.

Officials in Victoria state, which includes Melbourne, announced those orders would be lifted when 70% of over-16s are fully vaccinated. They projected that target would be reached around 26 October.

"Lockdown will end. The (limited) reasons to leave your home and the curfew will no longer be in place," Victoria premier Dan Andrews said, adding that a raft of restrictions would still be enforced.

Restaurants and pubs will be allowed to reopen but only with a maximum of 50 fully vaccinated people seated outdoors, while a ban on visitors to homes will remain in place.

But once the vaccination rate lifts to 80% - projected by roughly 5 November - fully vaccinated Melbourne residents will enjoy a greater range of freedoms, including no masks outdoors, up to 10 visitors to homes, and the option to work from offices.

Mr Andrews said the health system was likely to come under "intense pressure" as a result of the changes, but the staggered reopening would help Melbourne to "normalise" its virus response.

"We cannot perennially or permanently suppress this virus. Lockdowns have been about buying time to get to 70 and 80% vaccination," he said.

"We are fast approaching those milestones and at that point we have got to open the place up, because remaining closed forever has its own cost in every sense of that word."

The announcement came a day after several police officers were wounded and more than 200 protesters were arrested at a violent anti-lockdown demonstration in Melbourne.

Officers used pepper spray on the crowd, who defied stay-at-home orders to march through an inner-city suburb in opposition to pandemic restrictions.

Melbourne spent almost four months in lockdown last year, and has been recording hundreds of new cases each day despite enforcing strict lockdown rules.

After pursuing a "zero Covid" strategy for much of the pandemic, Australia has struggled to contain the more infectious Delta variant and state leaders are increasingly moving to ease restrictions once higher vaccination coverage is reached.

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Booster jab roll-out in UK

Booster jab invites are being sent out to more than a million people in England to "strengthen the wall of defence" against coronavirus created by the vaccines.

People will receive texts from tomorrow, while letters will be sent to those who are eligible later in the week, NHS England said.

Some 1.5 million people will be contacted and encouraged to use the National Booking Service.

NHS England said the vaccination of children aged 12 to 15 will also begin "shortly".

Those eligible for boosters include anyone aged 50 and over, people living and working in care homes for the elderly, and frontline health and social care workers.

All those who are clinically extremely vulnerable and anyone aged 16 to 65 in an at-risk group for Covid (who were included in priority groups one to nine during the initial vaccine roll-out) will also be eligible for a jab.

The Joint Committee on Vaccination and Immunisation (JCVI) has said people should receive their booster dose at least six months after they received their second coronavirus jab.

While there is a preference that people should get the Pfizer jab as a third dose, regardless of which jab they were initially given, the JCVI said half doses of the Moderna jab could be used as an alternative.

There are also booster campaigns in Wales, Scotland and Northern Ireland.

Health and Social Care Secretary Sajid Javid said: "It is excellent that getting your booster jab has now become even easier thanks to the opening of the National Booking Service to those eligible.

"Booster doses are an important way of keeping the virus under control for the long term and will protect the most vulnerable through the winter months.

"I urge everyone who receives a letter or text to get their jab as soon as possible so we can strengthen the wall of defence across the country that each vaccine brings."

Additional reporting - PA