Bushfire smoke blankets Australian city under Covid-19 lockdown

Smoke haze covered Australia's fourth largest city of Perth on Wednesday from a fast-moving bushfire that razed dozens of homes, complicating a tight lockdown after Western Australia state's first COVID-19 case in more than 10 months.

Authorities said the hot, dry conditions that had fuelled the fires in Perth's northeastern suburbs had eased slightly overnight.

"We had a better night than the previous night, we haven't had the fire impact any properties overnight and also some milder conditions have allowed us to complete some tracking," state Fire Services Commissioner Darren Klemm told reporters.

Klemm revised up the number of homes lost from the fires to 71 from 59 while urging residents to remain vigilant as erratic winds could reignite some fires. No fatalities have been reported from the fires, the origins of which are still unknown.

"It is going to continue to be a challenging fire for us for at least the next three or four or five days," Klemm said.

However, favourable weather could bring some respite with rains possible over the weekend and temperatures expected to drop to around 28 degree Celsius (82 degree Fahrenheit) over the next few days from the mid-30s, authorities said.

A tropical low in the state's north has brought heavy rains and gusty winds there and the system could move south bringing wet weather over the next few days, Australia's Bureau of Meteorology said.

Two million residents of Perth, the state capital, are under a five-day lockdown until Friday after a hotel quarantine worker tested positive to the highly contagious variant of COVID-19 first detected in Britain.

Residents must stay home, except for essential work, healthcare, grocery shopping or exercise, with visits to hospitals and nursing homes banned.

But state authorities said fire evacuation orders will take precedence over COVID-19 lockdown rules and residents should plan to shift to alternative places if emergency evacuation orders are issued.

"What we don't want is indecision from people about whether they should evacuate or not when we require them to evacuate, so that evacuation overrides any quarantining requirements that people may have," Klemm said.