A man has been seriously injured in an incident involving an excavator at a construction site in the suburb of Kambah.
WorkSafe has halted all work while it carries out investigations at the site, which is managed by Hindmarsh Constructions.
It is understood the man injured his leg and may have sustained other injuries in the incident on Wednesday evening.
The incident happened at a multi-residential construction site on the corner of Snodgrass Crescent and O'Halloran Circuit.
A separate residential construction site has been slapped with a prohibition notice after inspectors found "serious breaches" of health and safety regulations on Tuesday.
That site, in Coombs, was shut down after WorkSafe inspectors identified a number of breaches related to non-compliant scaffolding and electrical safety.
ACT WorkSafe Commissioner Greg Jones said the Coombs site would remain closed until the breaches had been fixed.
"The prohibition notice issued yesterday was effective immediately and closed down the entire multi-level residential apartment development in Coombs," he said.
"Major safety issues detected at this site included non-compliant scaffolding, numerous risk of falls from heights, and electrical safety."
WorkSafe inspectors would investigate the breaches to determine whether further regulatory action was warranted.
"As ACT Work Safety Commissioner I find it particularly disturbing that some construction sites continue to disregard basic safety procedures that are designed to keep workers safe," Mr Jones said.
The inspection had been carried out as part of a cross-border push alongside regulators from New South Wales.
"The current cross border construction inspections are focussed on scaffolding and falls from heights as well as electrical safety, site security, housekeeping and signage," Mr Jones said.
"Residential construction sites, medium commercial and single residential sites have been chosen for this round of proactive inspections."
Sites in Belconnen, North Canberra and the Molonglo Valley would be targeted in coming days, as would projects across the border in Googong, Queanbeyan, Murrumbateman and Yass.
The cross-border inspection project is part of a four-year plan to increase safety within the construction industry.