More than 2 million people in the state of Western Australia on Saturday began their first full day of a snap three day lockdown after a coronavirus outbreak in a hotel quarantine facility led to community transmission.

People in the state capital Perth and the neighbouring Peel region have been asked to stay home except for essential work, and medical and shopping purposes.

Ceremonies to honour Australia's military personnel on the Anzac Day holiday on Sunday have been cancelled. Last year, the coronavirus pandemic forced most traditional memorials to be cancelled across Australia for the first time in decades.

Anzac Day originally commemorated a bloody battle on the Gallipoli peninsula in Turkey during World War One. On April 25, 1915, thousands of troops from the Australian and New Zealand Army Corps (ANZAC) were among a larger Allied force that landed on the narrow beaches of the Gallipoli peninsula, an ill-fated campaign that would claim more than 130,000 lives.

Today, Anzac Day honours all Australian troops from all conflicts.

Australia's topflight A-League soccer match between Brisbane Roar FC and Perth Glory scheduled for Sunday has been postponed while an Australian football game between Fremantle and North Melbourne will go ahead, but there will be no crowd.

The latest lockdown was ordered after a returning traveller who tested negative on release from a Perth quarantine hotel later tested positive for Covid-19, with authorities suspecting he became infected while in the hotel.

The man spent several days in Perth and infected another person before his infection was diagnosed.

Having closed its borders more than a year ago, Australia lets mostly citizens and permanent-residents return from abroad. Returned travellers, however, except from New Zealand, must undergo two weeks of mandatory hotel quarantine at their own expense.

The hotel quarantine system, together with snap lockdowns and swift tracking limiting coronavirus has helped Australia to keep its Covid-19 numbers low compared with other developed countries, with just over 29,500 cases and 910 deaths.

The Australian Medical Association (AMA) urged on Saturday a review of the hotel quarantine system to prevent further outbreaks.

‘Everything that can be done in hotel quarantine needs to be done right now and, unfortunately, in Western Australia as in some other states, that is not the case,’ Omar Khorshid, AMA's president told the ABC national broadcaster.

‘There are still holes that can be plugged.’