The ACT Health Minister has praised the actions of three Canberrans newly diagnosed with COVID-19, saying each of them followed guidelines to minimise their transmission to others.

Key points: All three new cases had recently travelled overseas

All three new cases had recently travelled overseas Canberra's jail will suspend visits to inmates to slow the virus's spread

Canberra's jail will suspend visits to inmates to slow the virus's spread There are now nine confirmed cases of coronavirus in the ACT

But a search is still underway for people who may have come into contact with the infected people, including on Canberra-bound flights.

The cases, a man in his 70s and two women in their 50s and 60s, all recently returned from overseas travel and went into self-imposed isolation.

The announcement of three new positive results is the largest jump in COVID-19 cases in Canberra so far, bringing the total to nine.

ACT Health is now working on reaching the close contacts of the three, including passengers on flights used by two of the new cases while they may have been infectious.

The third case was not believed to have been infectious while she was travelling.

Authorities are looking to contact people sitting on rows 79 to 83 on flight QR908 from Doha to Sydney, which arrived on Tuesday March 17, and rows 12 to 16 on flight VA672 from Sydney to Canberra, landing at 9:30pm on the same day

They are also looking into whether passengers on flight QR906 from Doha to Canberra on Monday March 16 could have been exposed to the virus, though were yet to determine the infectious person's seat number on the flight.

The two women remain at home in isolation, while the man has been admitted to hospital.

Prison visits halted to stop virus spread

Health Minister Rachel Stephen-Smith said all three new cases had "done the right thing" by self-isolating to limit their contact with other people.

"It's an important reminder to those people who may have returned from overseas and are wondering whether they really do need to self-quarantine — yes you do," she said.

The ACT Government has also cancelled visits to Canberra's jail from Monday, in an effort to prevent the virus from spreading inside.

ACT Corrective Services Commissioner Jon Peach said one prisoner at the Alexander Maconochie Centre had been tested for coronavirus after exhibiting flu-like symptoms, but they had returned a negative result.

"We have to make sure that people put into the centre are protected … from the potential spread and we have to limit the number of people actually entering the jail," Mr Peach said.

"We have a number of prisoners that are obviously concerned about the virus, we've also got a number of prisoners that really, really want to see their families.

"We are working very very hard to ensure that there are opportunities for detainees to maintain those family ties, which would [include] increased access to telephones."

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In the ACT, more than 2,200 people have been tested for COVID-19.

Yesterday, the ACT Government released details of a stimulus package aimed at helping the territory to weather the economic storm the coronavirus outbreak has brought.

It includes a $150 rebate on bills for every household, credit for businesses and cash payments to public housing tenants.

Farmers markets allowed to go ahead amid social distancing

While several events in Canberra have been postponed or cancelled in the wake of the pandemic, farmers markets were allowed to go ahead over the weekend, as they are classified as an essential service.

Sarah Power, the manager at the Capital Region Farmers' Market, said staff had worked hard to accommodate for social distancing requirements.

Shoppers were encouraged to keep their distance at the markets. ( ABC News: Holly Tregenza )

"We've taken out all tables and chairs, removed them entirely, so that we are encouraging social distancing," she said.

"We've also spread the majority of our stalls out as much as we can so that allows people to distance themselves."

Food sampling has also been scrapped, but Ms Power said there had been no need to institute purchase limits on goods, as major supermarkets had done in response to panic buying.

"We are certainly up in terms of a lot of people but it's calm, it's orderly, people are forming lines and every one is really just happy to be here," she said.