Larissa Woonton of Yarralumla.

Larissa Woonton of Yarralumla. Photo: Melissa Adams

A bizarre demolition that forced a family of nine out of their home in prestigious Yarralumla could lead to a rewriting of planning regulations.

The neighbouring half of the family's two-storey duplex in Fraser Place was flattened to make way for a new, stand-alone home.

Larissa Woonton said she was inside with three of her seven children, terrified, when heavy machinery moved in last winter to demolish the other half of the 1951 building.

Owner of one half of a classic Canberra duplex is angry about their neighbour demolishing the other half in Fraser Place, Yarralumla.

Owner of one half of a classic Canberra duplex is angry about their neighbour demolishing the other half in Fraser Place, Yarralumla. Photo: Katherine Griffiths

''It was awful, the whole house just shaking,'' Mrs Woonton said. ''We heard it crashing and vibrating and went out into the backyard.''

After their initial fear, her daughter, 3, and sons, 4 and 5, watched, fascinated by the big orange machine pulling down half of the building.

The Woontons have a $5000-a-month mortgage on the home, which is on the market for $1.75 million. It is one of only six two-storey brick duplex homes that occupy 12 large blocks resplendent with pin oaks, maples and birches in the quiet cul-de-sac.

A $30,000 bill for legal and engineering fees and a ruling from the ACT government have brought them no closer to restoring the newly renovated, five-bedroom home, which has been declared a fire trap.

Mrs Woonton said she was informed of the demolition in a handwritten note in May last year from neighbours Darren Smith and Liz Broad, who were leaving for the London Olympics. Mrs Woonton and her husband, Brett, complained to the ACT Planning and Land Authority (ACTPLA) but demolition went ahead.

''How can something like this happen in the middle of Canberra without someone being accountable?'' Mrs Woonton said.

Ms Broad said they had sought and followed advice from a qualified certifier and engineer.

After a dispute and mediation, Ms Broad and Mr Smith were proceeding with ACTPLA's recommendations and instructions from another certifier and engineer.

The Woontons have been told they must wait for the new home to be completed before the interior common wall can be repaired and turned into an exterior wall.

The new home is exempt from a development application. The builder, Rawson Homes, is not commenting.

An engineering consultant found steel beams and electrical wires protruding from the common wall and exposed cavities, which were a fire hazard and open to weather, vermin and condensation.

The Woontons are living at Jindabyne, where Mr Woonton is a pharmacist.

''We have a strong case for civil action,'' Mrs Woonton said. ''It will take years. We can't commence legal action to seek damages until it is finished, which seems ridiculous. The reason I am so frustrated is ACTPLA made the decision and gave the other side three weeks to have mediation with us and to reach agreement and get the wall on the way.''

Planning Minister Simon Corbell replied to a neighbour's concerns, saying the problems were novel to the territory.

In a statement, ACTPLA said those involved needed a fair hearing and disciplinary action was not being considered at this stage. The regulator wanted to give mediation a chance to work.

The Environment and Sustainable Development Directorate was reviewing planning exemptions in relation to this type of development. Normally, an agreement between neighbours would have been reached beforehand but no agreement was in place. The neighbours have since signed an agreement.

''Mrs Woonton's neighbouring leaseholder has agreed to bear all costs for the works required to rectify Ms Woonton's exterior wall,'' the directorate said. ''Ms Broad is meeting with the builder … to discuss completion time and site access and the outcome of those discussions will inform any subsequent ESDD decisions to exercise statutory powers.''