But senior planning officials have conceded there is no process to ensure those buying off-the-plan are aware about proposed changes to their future property, prompting claims that the existing laws are flawed.

At budget estimates hearings this week, Greens planning spokeswoman Caroline Le Couteur asked what, if anything, the government was doing to stop developers lodging multiple applications to "significantly alter" approved project plans.

Ms Le Couteur said it appeared developers were using the tactic to reintroduce aspects of their original proposal which had been objected to, and subsequently removed, before approval was granted.

She singled out construction giant Geocon, which has lodged multiple applications to amend approved plans for its Republic development under construction in Belconnen.

In another case, the developer this year sought to scale up its $400 million WOVA complex in Woden, less than three months after their plans were approved on the condition that proposed building heights were lowered.

The ACT Planning and Land Authority rejected the application, ruling there was "no grounds" to allow the revision.

At this week's hearings, ACT Chief Planner Ben Ponton said he was aware and "very mindful" of the strategy, although he did not reference any particular developers or projects.

Mr Ponton said the authority had started attaching conditions to development approvals, which meant that future amendments, even those considered "ordinarily minor", were subjected to reassessment, rather than waived through as they would have previously.

He said the government architect was also being called in to evaluate major design tweaks.

"We are certainly mindful of this issue and we are working to address that," Mr Ponton said.

"It will be a case of incremental change. We will try new avenues and if it works, then great, but we will continue to refine it."

Ms Le Couteur was pleased with the government's commitment to act on the issue, but remained concerned about how and when the community was consulted on proposed amendments.

After Geocon applied to amend plans for its 800-home WOVA complex, only those who provided feedback to the original application were informed.

The planning directorate's senior director of development assessment, George Cilliers, said the authority had the discretion to determine whether the new plans should be subjected to a fresh round of public consultation.

Mr Cilliers said in making that judgment, it considered if the proposed change would "detrimentally affect" the same people who had provided feedback to the original proposal. The extent of the changes were also considered, he said.

But Mr Cilliers conceded that consultation couldn't extent to people who had bought apartments at the proposed development, because the government did not know who they were.

Mr Ponton added that there was no legal requirement for developers to alert buyers about the changes, which Ms Le Couteur described as "possibly a defect in our legislation".

However, Geocon's director of planning and development, Dan Stewart, said the company used a variety of mechanisms to contact buyers and stakeholders about changes to its developments.

Mr Stewart refuted Ms Le Couteur's allegations about the motivations for lodging amendments.

"Amendments cost time and money, and in a perfect world we would work to one set of plans," Mr Stewart said.

"We apply for amendments to either improve the design, accommodate unforeseen or emerging market demands or to improve the eventual outcome for the community."

As an example, Geocon had to lodge an amendment to its Republic development to accommodate the "very specific requirements" of a planned Woolworths supermarket, Mr Stewart said.

Master Builders Association of the ACT chief executive Michael Hopkins said it was normal for developers to make minor variations to their proposals, as they responded changing market conditions, client wishes and building practices.

Owners Corporation Network president Gary Petherbridge said buyers had every right to be frustrated by the tactic, which happened "all the time".

Mr Petherbridge same amendments should be subject to the same consultation and notification requirements as original applications.