Larissa Woonton.

Larissa Woonton. Photo: Melissa Adams

Larissa Woonton, the mother of seven who sat with her children inside her Yarralumla home terrified while neighbours bulldozed the other end of the duplex, is rejoicing at legislation to prevent it from happening again.

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

Under changes to planning laws, the new home was exempt from a development application.

The Yarralumla duplex that was flattened earlier this year.

The Yarralumla duplex that was flattened earlier this year. Photo: Katherine Griffiths

Environment and Sustainable Development Minister Simon Corbell has announced duplex houses will need development approval before they can be demolished or substantially altered.

In a statement Mr Corbell said a DA would give neighbours  an opportunity to review the plans and make comments and ensure the planning authority could assess the proposal against current laws and standards to protect the amenity and integrity of the adjoining dwelling.

Mrs Woonton, who had listened to heavy machinery move in last winter to demolish the other half of the 1951 building, said the change was overdue.

''Our biggest concern (afterwards) was that nothing was happening to prevent this from happening again.

''That's fantastic, that was our whole argument.  They left our common wall completely exposed to the weather and our building was not structurally sound.''

The family's other concern was the character of the duplex was being compromised.

''What they did in our street really altered the character of the street,'' Mrs Woonton said.

''None of the neighbours, and especially us, didn't have an opportunity to have any input or consultation.''

The remaining duplex is back on the market, after the Woontons sought a boundary adjustment. They are awaiting the Land Titles Office to re-register two new blocks.

''We have had to go through that so we own the new wall. The boundary will come out and around that new wall on our building.

''It has been an absolute shemozzle. The certifier used a loophole in legislation to bulldoze ahead, quite literally."

Legal action was ongoing.

Mr Corbell said the changes came about due to his concern over the circumstances surrounding the redevelopment in Fraser Place.

He said discussions about the changes had taken several months and included feedback from community groups.

“They expressed a view that this is a problem and I agree with that,” he said.

Inner South Community Council chairman Gary Kent said the changes were "exactly what we're asking for".

Mr Kent said the council was grateful for the altered laws, which could affect the many people living in duplexes in the inner south.

"There's a lot of development in the inner south and a lot of duplexes," he said.

"We have had some concerns about development where we felt that neighbours were disadvantaged."