It has been more than two years since the initial excavation on the site bordering Suzi Maginnity's property began and the new house is now close to completion.

A report by Coffey engineers, commissioned by Mrs Maginnity, found the risk to life estimation of the cliff was above the tolerable level, and the risk to property was very high. It stated such risks were "unacceptable without treatment".

A stoush has ensued between her family and owner-builder Kurt Muench, who both believe they have followed due process.

Mrs Maginnity described the stress of waking up during the night just to check her swimming pool hadn't slipped down into the neighbour's yard.

The saga began for Mrs Maginnity, her husband and daughter, now 10, in May 2014. She said in the weeks following the excavation, their boundary fence and upper retaining wall fell into the excavated hole.

She said the boundary between blocks is now empty space as the earth beneath it has fallen away, encroaching on her backyard, part of which is inaccessible due to the danger of the drop.

The temporary "safety fence" erected by Mr Muench is made from plastic corrugated sheeting and rusted metal mesh and butts onto the Maginnity's patio, an area they no longer use regularly. Temporary shotcrete has been applied to parts of the excavated wall.

WorkSafe has attended the site multiple times during the construction of the home and in January of this year issued prohibition and improvement notices.

A stop work notice was issued in March but it allowed the building to reach lock-up stage.

ACT WorkSafe commissioner Greg Jones said the original proposal did not include an excavation that close to the boundary.

Mr Jones said there would be a "normal expectation" an excavation of that size would require an engineering approved retaining wall to protect the building, the workers on the site and to secure the land above.

Housing Industry Association executive director for ACT/southern NSW Greg Weller said he could not understand how such a substantial cutting could not be retained before other works started.

"It would have been expected at the point of the slab being poured, at which point questions should have been as to why the wall wasn't retained," Mr Weller said.

"It's something that should have been dealt with before the house got to this point."

However, the builder, Mr Muench, maintained he followed due process.

"Kurt is a fully licensed builder with over 50 years' experience," a spokeswoman for Mr Muench said.

"Regular meetings and discussions have taken place between relevant parties and ACT Planning and Land Authority."

ACT Planning and Land Authority refused a development application for a retaining wall in May this year, after a request for additional information was not provided.

Mr Muench said he had tried to contact Mrs Maginnity's engineer multiple times with no response. For her part, Mrs Maginnity said no such contact had been made. He claims this has stalled the process of putting the necessary retaining wall in place.

An engineer for Mr Muench said the initial retaining wall and fence on the neighbouring property collapsed due to being built on fill, not through the fault of the builder.