Turnbull double act call for 'more density, everywhere'

Though the former coalition prime minister said negative gearing would do little to improve housing affordability in the long run, and touching capital gains exemptions for main residences would be political "kryptonite".

Speaking at the National Press Club on Wednesday, the double act said it was troubling to see young people giving up on the dream of home ownership.

"There is a housing crisis, where housing is so expensive, young people cannot buy unless they've got the bank of mum and dad behind them," said Ms Turnbull, a former Sydney mayor and urbanist.

"This is something which I think is not acceptable," she said.

Mr Turnbull said "NIMBYism", or the "not in my backyard" movement, was part of the problem.

"If you take it too far, it basically means that no one will be able to afford to live in that area," he said.

The pair offered up a plethora of ideas to fill in the "missing middle", which refers to smaller apartment blocks, townhouses and other denser housing types that are noticeably rare in Australian cities.

Regulatory settings can be a barriers, such as apartment design quality regulations in NSW that Ms Turnbull said had actually made infill three storey apartments "impossible" to build.

Building homes from patterns or template designs, as done in suburbs like Paddington in Sydney during the 19th century, would also make approval processes easier.

Ms Turnbull also suggested a low income tax credit that has successfully delivered millions of affordable homes in the United States. Paving the way for more build-to-rent development is also key.

She also said it was important to carefully balance housing supply demands with competing interests such as heritage considerations.

"There should be more density absolutely everywhere, but people think density and they think 50 storey towers," Ms Turnbull said.

"What they've got to think about is Paris, and Rome, and not Manhattan."

Australian Associated Press