Mrs Maginnity has been fighting for access to her own backyard after the excavation resulted in a six-metre cliff face between her and her neighbour's block.

Initially the development work, which was not authorised to be conducted to that extent as it encroached on the Maginnity's boundary, resulted in a landslide and slumping of part of the backyard. In the intervening years, and after sprayed concrete was applied to try and stabilise the wall of dirt, more of Mrs Maginnity's land has slipped onto the neighbour's block and resulted in damage to her pool, the pavers surrounding it and her pergola.

The builder, who believes he has followed due process, was allowed to continue to build on the site despite nothing securing the six-metre wall of dirt. A stop-work notice was issued in March, 2016 with construction allowed to continue to lock-up stage.

In 2016, an engineering consultant commissioned by Mrs Maginnity said the situation was "a risk to life and property".

Despite Mrs Maginnity's pleas, the government has only recently stepped in to rectify the situation.

"The regulators and enforcers are pitting us against each other," Mrs Maginnity said.

"And that's not fair, on either of us. I don't care what they do next door, it's none of my business, but the government have put me in this situation," she said.

The initial excavation occurred in May 2014 and resulted in "safety fence" being erected on Mrs Maginnity's block. The fence, made of rusted metal and plastic that bangs in the wind, initially didn't prevent access to the cliff face for her then eight-year-old daughter.

At the start of the process, Mrs Maginnity had an engineer look over the plan for the wall.

"I thought I better get someone to check it because this was allowed to happen to start with," she said.

"So it's cost me from the start, which is ridiculous."

There have been nine designs for a retaining wall over the past four years, none of which have resulted in a permanent stabilisation.

"I keep saying, why is this my job [to fight to rectify the situation]? All along the government has suggested I needed legal help, so being the helpful person I am, I now have a lawyer who I need to pay.

"I'm trying to do the right thing in doing what they suggest, but I still don't think it's my job."

Mrs Maginnity said it has been four years of angst, and there was little hope she would be able to recover the money she's spent on her neighbour's problem.

"Why is it my burden to shoulder? They're outsourcing enforcement to the little lady next door and it's just not fair."

She said after 16 years of living at the home, the family now feels trapped by their situation.

"This is a beautiful spot but we're trapped. We can't sell the house with that there. We're stuck. I work to pay these bills," she said.

A spokeswoman for the builder on the site next door, Kurt Muench, said all certification of the site was undertaken by a fully-qualified and approved certifier.

The spokeswoman said the government had been helpful in trying to resolve the issue.

"Together with the ACT government, we are in negotiation with Mrs Maginnity to reach agreement."

The spokeswoman had previously said that Mr Muench was a fully licensed builder with more than 50 years' experience. An engineer for Mr Muench had stated in 2016 that the initial retaining wall and fence on the neighbouring property collapsed due to being built on fill, not through the fault of the builder.

ACT Construction Occupations registrar Craig Simmons, who started in the job in February, stepped in on Friday to deliver an ultimatum.

He said it had taken four years because the engineers involved couldn't agree on a solution, but he was now willing to intervene and side-step the development application process to "expedite" the works.

"There's a power available to the registrar to direct building work to take place," Mr Simmons said.

"[At a meeting on Friday] I said these are the options you have, and I have asked the parties to come back to me by Thursday of next week with the preferred method to proceed. Once I get that, then I will proceed as expeditiously as possible to have the site made safe by the building of a wall."

Mr Simmons couldn't pinpoint why it had taken the government so long to step in, or so much money on Mrs Maginnity's behalf to come to this, but he said the onus was not on her.

"That's a choice people make," he said.

Minister for Regulatory Services Gordon Ramsay visited the site in 2017 and said he had taken advice from experts and Access Canberra that showed the site was "safe".

"I understand the site was stabilised when the issue was first raised and there have been subsequent checks of the site including by engineers, which have advised the site is safe," the minister said.

Canberra Liberals planning spokesman Mark Parton also visited the site and described it as a "pure debacle".

"Here we have a Tuggeranong homeowner who, through no fault of her own, finds herself out of pocket to the tune of tens of thousands of dollars," he said.

"What Suzi has gone through is deplorable and has come as a result of unenforced legislation, rather than a lack of regulation."

Mr Parton said ministers had "failed to open channels of communication" between government agencies, meaning that regular citizens "who don't have a PhD in town planning find it nigh on impossible to navigate this maze of bureaucracy".