Canberrans have struggled to find the P2 masks - which can filter smoke particles - at hardware stores like Bunnings and at chemists, with stock sold out.

Deputy Chief Minister Yvette Berry said the government was working on shoring up a supply of masks especially for vulnerable in the community.

But she warned masks were not an alternative to avoiding the smoke by staying inside.

"The government has provided masks where it's needed for people who are regularly working outside," she said.

"But I think it's important to make sure that the community gets the message about what the mask actually does, what sort of protections or comfort that might provide to people.

"These are unprecedented smoky conditions we are experiencing in the ACT."

Chief Health Officer Kerryn Coleman said the P2 masks had many limitations and were only effective if fitted perfectly.

They also do not work once moist, she said.

"So generally, we're not recommending that people in the community need to use P2 masks because of those limitations about their effectiveness," she said.

"And we're encouraging people to please stay out of the smoke as much as possible."

The smoke has also affected Canberra Hospital, with two MRI machines out of order on Thursday because of it.

Ms Coleman said one was back working by the afternoon while the other was expected to be working in the near future.

"But the hospital is well equipped and used to managing demand and prioritising those procedures ... so there are no negative impacts," she said.

Canberra GP Antonio Di Dio said the relentlessness of the smoke was making some people anxious.

"People need to be aware about their own health and those very young and very old," he said.

"Also be very careful if they've got asthma and lung disease or they're a smoker. Be careful about going outside if it's not necessary to do so.

"He said people should take precautions, but it was important not to become obsessed about the smoke from a health perspective."

Doctors have been seeing more and more patients who are affected by the smoke haze.

"There are more coughs, more asthma, more shortness of breath and exacerbations of known respiratory conditions," Dr Di Dio said.

He said people with mild asthma were increasingly affected.

"They are at risk because they don't really know what to do because it's been years since they had an episode," he said.

He said the severe weather conditions should be a starting point for a collaborative and respectful conversation about how to act on climate change.

"Some people are suffering right now, many other people will suffer if this situation continues," Dr Di Dio said.

"We need to be sensitive and care for each other and be collaborative."

Asthma Australia senior manager programs Nigel Cooper said the smoke haze could cause an inflammatory response in people with low or controlled asthma that could last weeks.

"It take a while for the swelling [from inflammation] to come down again," he said.

"Be really prepared these are unprecedented conditions for people who think their asthma is well controlled."