One mistimed supermarket run and you could find yourself needing to get a COVID test, in isolation or worse: picking up the virus along with your bread and milk.

After a spell in 14-day quarantine in a share-house, Milan Leonard wanted a more considered approach to grocery shopping in lockdown.

"Our house had been in isolation for a couple of weeks before that, because one of my housemates was at the pub the day before we had our first case, and getting quite unlucky," Mr Leonard said.

"And then a couple other of our housemates have quite bad COVID anxiety, and so I thought, you know, on the day that we're getting out and raring to get back to the shops because we've run out of supplies, may as well figure out the safest time to go."

Mr Leonard, an honours student in physics who has worked in data science, analysed ACT Health's list of exposure sites, looking for the best time to go to the supermarket, to minimise the risk he and his three housemates would encounter the virus again.

Across Coles, Woolworths and IGAs in Canberra, the hour between 5pm and 6pm has had the most number of notifications for COVID-19 exposures.

The best time to go to the supermarket, Mr Leonard's analysis showed, was early in the morning, and in the evening. The number of exposures were much lower after 7pm.

Mr Leonard said in an ideal world, one person would shop for everyone in the share-house.

"Trying to organise four 20- and 21-, 22-year-olds to get their shopping done and figure out what they want to eat two weeks in advance is definitely not going to happen," he said.

About one-fifth of the 827 exposure sites and times identified to noon on Wednesday were at supermarkets, which have put pressure on supermarket workers forced to isolate.

The Shop, Distributive and Allied Employees Association has lobbied the ACT government for priority vaccinations for supermarket and takeaway food workers.

"The ACT government acknowledges that there are many essential workers who due to their age have only recently become eligible for a vaccination. However, it is not possible to vaccinate everyone at once," a spokesman for ACT Health said.

A spokesman for Woolworths said hundreds of supermarket staff members had needed to isolate during the ACT outbreak, and they were being encouraged to get vaccinated.

"We're actively recruiting for team members across the ACT to help us provide the food and essentials our communities rely on both in-store and online," the spokesman said.

A spokeswoman for Coles said the supermarket's staff members were also encouraged to get vaccinated.

"Where a store is particularly impacted by team members in isolation, we rotate team members from other stores and utilise labour hire to assist with tasks like stocking shelves and replenishment," the spokeswoman said.

READ MORE COVID-19 NEWS:

The majority of exposure sites identified since the start of Canberra's lockdown, on August 12, have been casual or monitor-for-symptoms sites, meaning the risk of contracting COVID-19 was lower. No supermarkets have been identified as public sites of transmission.

Deputy chief health officer Dr Vanessa Johnston on Wednesday said health authorities were not focused on the number of exposure sites being identified in the community, but were assessing the risk they posed.

"I think you'll note that most of those sites [identified in the past few days ] are casual or even monitor for symptoms, where we don't actually request or require anyone to have a test. They're much lower risk," Dr Johnston said.

Our journalists work hard to provide local, up-to-date news to the community. This is how you can continue to access our trusted content: