But the ACT Civil and Administrative Tribunal has finally overturned ACTPLA's decision to approve a controversial redevelopment of the Woolworths' car park in Dickson after a long-running appeal.

In a decision handed down late on Thursday, the tribunal determined the proposed development broke too many planning rules to be mitigated by conditions placed on its approval.

It will mean Coles will have to re-submit a revised development proposal for the site. A Coles spokesman would not say whether they planned on appealing the decision, but said they would read the judgement carefully.

ACT Chief Planner Ben Ponton said the planning and land authority would look at the decision to determine what lessons can be learned from this and if further planning reforms were required.

Mr Ponton said the authority respected the tribunal's decision but noted in the last year, 19 of 20 decisions that went to ACAT for review came back in ACTPLA's favour.

But Greens crossbencher and former Downer resident Caroline Le Couteur, who was was one of the original objectors to the development, said the "planning system was broken".

She said she was disappointed ACTPLA could approve something that had been "so completely demolished by the tribunal" and this case was one of the reasons the Legislative Assembly's planning committee had announced an inquiry into development applications.

"I do regret that it's taken the commitment of the community to get this action. It's not fair on the community or on the commercial developers," Ms Le Couteur said.

"If Woolworths wasn't indirectly involved there's no way the community could have funded this."

Dickson resident Ron Brent said while he was confident they would win the "one-sided battle", he was pleased the tribunal had chosen to protect the character of Dickson.

Town planner Jane Goffman, who gave evidence during the hearing, said she was really grateful that the tribunal had confirmed "what we knew all along".

Ms Goffman said they did not face a level playing field in the appeal, with a transcript of the proceedings alone costing $20,000.

"We couldn't have pooled the resources unless Charter Hall backed us up," she said.

North Canberra Community Council chair Denis O'Brien encouraged Coles and ACTPLA to get together soon to find a development that would fit with planning rules, the community's expectations and their commercial requirements and expediate its construction.

Ms Goffman said locals were hanging out for a second and third supermarket, especially the Aldi, but wanted the development to be sympathetic to the surrounding group centre.

Coles' development arm first lodged plans to build two supermarkets and 155 apartments on the car park on the corner of of Antill and Badham streets in late 2014.

But the developers were sent back to the drawing board in early 2015 after local residents and businesses complained about its impact on traffic and pedestrian safety.

Their main concern was the "mall" Coles wanted to build would cut off pedestrian access to the Dickson group centre, strangling small businesses and activity in the eclectic courtyards.

The ACT government gave the green light to scaled back plans in June 2016, however residents said there were still traffic and accessibility problems with the new development.

Woolworths' landlord Charter Hall filed an appeal against the approval in July 2016, with the North Canberra Community Council and Downer Community Association as joined parties.

Mr Brent told Fairfax Media locals weren't against the development and were desperate for another supermarket, but did not want it at the "price of the character of Dickson".

"They're essentially building a moat around the new development that will isolate it from the rest Dickson," Mr Brent said.

The tribunal reserved their decision last March after 15 days of hearing.

The Woolworths car park is not one of the blocks of land at the centre of the controversial Dickson landswap, however its fate is tied to it.

The Land Development Agency made the complicated land deal with the Dickson Tradies to trade the government-owned car park next door to their club for the CFMEU headquarters and old Downer Club in 2014.

However the Tradies Club will only pay for the land once the Coles development is finished to ensure there is still parking in the area.