Canberrans are among those most likely to lose out from any tax changes targeting negative gearing, new analysis has shown.

The Grattan Institute figures showed 13 per cent of ACT taxpayers were negatively geared in the 2012 to 2013 financial year.

The national average was 10 per cent, and only the Northern Territory had a slightly higher proportion, at 13.2 per cent.

"Say for a person earning $80,000, if they live in the ACT they are more likely to negatively gear than someone earning $80,000 in New South Wales," Grattan Institute chief executive John Daley told 666 ABC Canberra.

"And then, of course, there's also the effect that essentially people in the ACT tend to have higher incomes and generally people on higher incomes are more likely to negatively gear."

Prime Minister Malcolm Turnbull has flagged negative gearing is in his sights.

But some Liberal MPs have expressed concerns any changes could have negative consequences for the party.

The Opposition's policy, which it will take to the election, would see only new properties negatively geared after July 2017.

Mr Daley said those on higher incomes tended to save more with negative gearing.

"That one-fifth of taxpayers earning $80,000 or more accounts for about one-third of people negative gearing, and it accounts for about 70 per cent of the tax benefit of negative gearing," he said.

"The remaining 80 per cent of taxpayers earning less than $80,000 a year, they're only getting 30 per cent of the benefit of negative gearing.

"So maybe there are some ordinary mums and dads who are negative gearing, but by and large the people who are doing it more often, and certainly the people getting the highest benefit are those who are doing much better than the rest of Australia."