ACT auditor-general Maxine Cooper is calling for tighter planning processes after finding some houses built in Canberra should not have been approved.
Mike Hettinger from the North Canberra Community Council wants to see stronger checks by planning authorities on building projects listed as exempt.
Under the current planning system, a house can be built in an existing residential area without development approval, provided a private building certifier checks it complies with certain rules.
After examining seven case studies, Dr Cooper found that two of the houses should not have been approved.
Dr Cooper says monitoring of certifiers was inadequate.