Mr Albanese returned the positive result during a regular PCR test on Thursday afternoon, but was not symptomatic.

The Labor leader was set to fly out of Sydney for Western Australia as part of his campaign trail.

Mr Albanese said he would isolate at his Sydney home for seven days and was feeling fine despite the diagnosis.

"While at home I will continue my responsibilities as alternative prime minister and will be fighting for a better future for all Australians," he said in a statement.

"I am grateful to know that I will have access to the world's best health care if I need it, because of Medicare."

Prime Minister Scott Morrison sent best wishes to his election rival.

"Everyone's experience with COVID is different and as Labor's campaign continues, I hope he does not experience any serious symptoms," Mr Morrison tweeted.

Labor frontbenchers are expected to have an increased role in the campaign as the opposition leader isolates.

Mr Albanese, who spent Thursday campaigning on the NSW south coast and in Sydney, is also likely to conduct virtual press conferences should he still be feeling well.

On Wednesday night he had faced off against the prime minister during the first leaders' debate of the election campaign.

Labor frontbencher Chris Bowen wished the Labor leader a speedy recovery.

"My advice is to rest up, because there is much work to do when you're out of isolation to win this election and then a huge amount of work to do to give Australia a government we can be proud of," he said on Twitter.

Greens leader Adam Bandt also wished Mr Albanese well.

"In the meantime, I hope election 2022 can shift to a hybrid workplace mode and that we still get to see you on our screens," he said.

Earlier on Thursday Scott Morrison said he was deeply sorry for the offence caused by saying he felt "blessed" to have children who did not have disabilities.

The prime minister made the comment during Wednesday night's leaders' debate, sparking a major backlash.

"I meant no offence by what I said last night but I accept that it has caused offence to people ... and deeply apologise for any offence it caused," he told reporters in Brisbane.

"I wasn't trying to imply that I could first-hand understand the challenges people face in those situations.

"I was seeking to respect the challenges they face, not the opposite. I would hope that people would accept that at face value."

Labor campaign spokeswoman Katy Gallagher said the comment was insensitive and hurtful.

"As the parent of a wonderful daughter with autism, I was really upset by that comment. I found it really offensive and quite shocking," Senator Gallagher told the Seven Network.

"People who have a disability, children with autism, it is a kind of response they get all the time that people are blessed not to have what they have, when in actual fact every child is a blessing."

But Liberal senator Hollie Hughes, who has a son with autism, defended the prime minister's comments.

"I certainly didn't take anything negative away from it. I know there were days, very early on when my son was younger, that were really, really hard. I didn't feel particularly blessed," she told the ABC.

"We have a much higher suicide rate within the autism population. We have a higher unemployment rate than the general disability population. There are issues we can be angry about."

Australian of the Year and disability campaigner Dylan Alcott tweeted: "Woke up this morning feeling very blessed to be disabled - I reckon my parents are pretty happy about it too.

"Feeling sorry for us and our families doesn't help. Treating us equally, and giving us the choice and control over our own lives does."

Australian Associated Press