Police established COVID-19 checkpoints on Limestone Avenue near the Australian War Memorial and King Edward Terrace in Parkes near Questacon.

At the NSW-ACT border, a larger checkpoint was established on the Barton Highway near Hall.

ACT Chief Police Officer Neil Gaughan on Wednesday said Canberrans should expect to see more checkpoints within the city.

"We will start to do more random-breath-testing-type activity through areas of national institutions around Parkes and Barton," he said

"People in NSW-registered vehicles, we'll be pulling them over and having a chat."

Deputy Commissioner Gaughan said interstate tourists would be the focus of the operation, rather than residents of NSW towns bordering Canberra who perhaps work in the ACT.

"We obviously won't be doing Canberra Avenue because we get Queanbeyan traffic, " he said.

"But we'll do Northbourne Avenue, Belconnen Way, inner-city areas where tourists will be."

Deputy Commissioner Gaughan said checkpoints on large highways near the border worked as a deterrent to people who should not enter the ACT.

"We're obviously not saying when we are opening and closing those checkpoints," he said.

In terms of public transport into the ACT, he said police were in close contact with bus operators, who had provided manifests to ACT Policing. NSW trains will now terminate at Queanbeyan.

Deputy Commissioner Gaughan encouraged Canberrans to inform police if they were aware of people in the ACT who should not be in the territory, and said police wouldn't hesitate to hand out fines to people blatantly flouting the public health order.

He also defended the scale of the border checkpoint operation.

"If we look at what's occurring across world and across Australia with coronavirus, I think it is appropriate to allocate significant resources to the health direction," the deputy commissioner said.