Authorities issued a stop-work notice on Geocon's large-scale Republic building site in Belconnen on Thursday, after earlier knocking back amendments to a development application for the site.
The developer confirmed work on the site had stopped but said the issues were minor and technical and there was no impact to building safety.
Access Canberra issued the notice after identifying work that was allegedly inconsistent with building approvals for the site.
ACT Construction Occupations Registrar Ben Green said building work on the site was prohibited while the notice is in place, unless it was to bring the building back into compliance with the building approval.
"We will continue to investigate this matter and work with the parties involved to ensure a timely resolution," he said in a statement.
"This is yet another reminder that we will take action where it is identified that building work has occurred without the required approvals in place."
Geocon said in a statement that it was working with relevant authorities to have the matter rectified and the $1 billion mixed-use residential project would still be delivered ahead of schedule.
"This will come as welcome news to the 750 purchasers who have already secured an apartment in Republic," the statement said.
Minister for Building Quality Improvement Gordon Ramsay said government inspectors were cracking down strongly on building sites and the government had invested in strengthening enforcement activities.
"We will not tolerate building work that cuts corners, delivers poor quality work, or which does not adhere to necessary approvals," he said.
"Everyone in the industry is on notice that the work must be of the highest quality and built according to the rules so that Canberrans can rightly have full confidence that our buildings are safe and will stand the test of time."
The ACT Planning and Land Authority, in the reasons for refusing the amended development application, found Geocon's plans and documentation did not match the amendments applied for.
"The amendments that were applied for as per the application form and supporting statement dated 10 April 2019 did not accurately reflect all changes made to the plans, drawings and other documentation that were submitted as part of this application," the decision said.
"A number of discrepancies were identified and not listed as changes on the supporting statement or application form. Due to the inconsistencies between the stated amendments in the application and changes shown on the supporting plans, it is not possible to assess the application in its current form.
"A new application is required which lists all amendments and is accompanied by consistent and accurate supporting plans, drawings and other documentation."
The application for amendments included changes to parking arrangements, service and refuse rooms, waste management, stair locations and basement vehicular movement.
The changes also included a reconfigured substation, the relocation of a public lift, a modified internal road, changes to the internal configuration of the hotel and changes to external finishes.
ACT chief planner Ben Ponton told ACT budget estimates last month the authority was "very mindful" of the strategy.
Geocon's director of planning and development, Dan Stewart, at the time said amendments were costly and it would be better to work to one set of plans.
"We apply for amendments to either improve the design, accommodate unforeseen or emerging market demands or to improve the eventual outcome for the community," he said.
The Canberra Times understands some workers on the Republic site were told to stand down on Friday.