Canberra’s coronavirus outbreak has grown to 45 cases as the nation’s capital records another 17 infections.

ACT Chief Minister Andrew Barr warned on Tuesday that case numbers would likely grow during a three-week lockdown that will last until September 2.

He has implored people to stay at home and flagged a compliance crackdown on essential businesses allowed to remain open.

“We are requiring businesses to take all reasonable steps to ensure that anyone who enters their business gets what they need, and leaves promptly,” Mr Barr said.

He was concerned about people loitering around shops without adequate social distancing.

• See all of the exposure sites in the ACT here

The territory had 17 infections following 7380 tests conducted on Monday.

No cases are in hospital and 37 are linked to existing infections.

The other eight, including the ACT’s first case in 13 months, remain under investigation.

Among a growing list of exposure sites are the Canberra Institute of Technology Reid and Bruce campuses attended by three people who were infectious.

Transmission is confirmed to have occurred at six settings in Canberra.

These include the city’s Fiction nightclub linked to six cases.

Four cases are linked to Lyneham High School, and three each to the Gold Creek School and Downer Community Centre.

No additional cases have emerged at Tuggeranong’s Greenway Views village, where an aged care worker did three shifts while infectious.

All residents and every staff member onsite were tested on Monday.

Health authorities are prioritising close contacts for testing amid lengthy queues as more than 7500 people quarantine.

The outbreak casts doubt on the return of federal parliament next Monday, after Mr Barr urged Prime Minister Scott Morrison to consider postponing it.

Parliament House is classified as an essential workplace, meaning it can remain open subject to tight restrictions.

-AAP