MELBOURNE (REUTERS) - Australia eased its international border restrictions on Monday (Nov 1) for the first time during the pandemic, allowing some of its vaccinated public to travel freely and many families to reunite, and sparking emotional embraces at Sydney's airport.

After 18 months of some of the world's strictest Covid-19 border policies, which banned citizens from coming back into the country and leaving it, unless granted an exemption, millions of Australians in Victoria, New South Wales and Canberra are now free to travel.

A flight by flag carrier Qantas Airways from Los Angeles touched down in Sydney at 6am, Australia's biggest airline said, the first in months to let vaccinated Australians walk off a plane without quarantining.

International travellers also arrived in Sydney via Singapore Airlines early on Monday.

Some travellers were also welcomed by airline staff holding banners and gifted Australian wildflowers and chocolate biscuits.

"Little bit scary and exciting... I've come home to see my mum because she's not well," said Mr Ethan Carter after landing on a Qantas Airways flight from Los Angeles.

"So it's all anxious and excitement, and I love her heaps and I can't wait to see her," he said, adding that he had been out of the country for two years.

In Melbourne, a water cannon sprayed a Singapore Airlines plane in celebration as it taxied down the tarmac after landing.

While the initial flights are limited to Australian citizens, permanent residents and their immediate families, they set in motion a plan to reopen the country to international tourists and workers, both much needed to reinvigorate a fatigued nation.

Thailand is also welcoming vaccinated tourists, without quarantine, from Monday, as is Israel, in a boost to global air travel after a trying 18-month period.

Australian Treasurer Josh Frydenberg told the Australian Broadcasting Corp on Monday that the travel changes would immediately aid the economy.

"It's a day for celebration - the fact that Australians can move more freely in and out of our country without home quarantine, if they're double-vaccinated," Mr Frydenberg said.

Television and social media footage showed tearful family reunions, with strict travel rules previously prohibiting many people from attending significant events, including weddings and funerals.

The relaxation of travel rules is tied to rising vaccination rates, with more than 80 per cent of people aged 16 and older in Australia's two most populous states, New South Wales and Victoria, as well as the capital territory, fully vaccinated.

Australians and permanent residents living abroad may now return, with Foreign Ministry data showing about 47,000 people are hoping to do so.

Most tourists - even vaccinated ones - have to wait to come to Australia, although vaccinated tourists from New Zealand will be allowed in from Monday.

Citizens of Singapore will be able to travel to Australia, without quarantine, from Nov 21.

Unvaccinated travellers will still face quarantine restrictions and all travellers need proof of a negative Covid-19 test prior to boarding.

The change in travel rules, however, is not uniform across Australia, as the country's states and territories have differing vaccination rates and health policies.

Western Australia, which has one of the world's biggest iron ore precincts, remains largely cut off from the rest of the country - and the world - as the state tries to protect its virus-free status.

"We still have a long way to go in terms of the recovery of our sector, but allowing fully vaccinated Australians to travel without quarantine will provide the template for bringing back students, business travellers, and tourists from all over the world," Sydney Airport CEO Geoff Culbert said.

Australia closed its borders at the start of the pandemic and let only a limited number of citizens and permanent residents return from abroad, subject to an exemption and a mandatory 14-day quarantine period in a hotel at their own expense.

But as it switched from a Covid-19-zero management strategy towards living with the virus through extensive vaccinations, borders are gradually reopening.

While the Delta variant outbreak kept Sydney and Melbourne in lockdowns for months until recently, Australia's Covid-19 cases remain far lower than in many comparable countries, with just over 170,500 infections and 1,735 deaths.

Around 1,500 people were scheduled to fly in to Sydney and Melbourne on Monday, according to the Board of Airline Representatives of Australia, an airline industry group.

Australian officials on Monday added India's Covaxin vaccine and another made by China's Sinopharm to a growing list of accepted vaccines, expanding the number of people who will be allowed to travel to Australia without quarantine.