This is despite a succession of public servants and Government ministers repeatedly dismissing accusations the dramatic explosion in the price per square metre paid for residential real estate in greenfields developments over the past decade was policy driven.

Chief Minister Andrew Barr has given profit targets in directions to the newly formed City Renewal Authority and the Suburban Land Authority for the next three years last week.

These have included some truly mind blowing profit targets for the period to 2021.

The Government is banking on the Suburban Land Agency, which takes over the bulk of the responsibilities formerly vested in the frequently maligned Land Development Agency, making $2.189 billion in land sales to the end of the 2020-2021 financial year.

That is more than twice the cost of the first stage of the controversial light rail project.

The City Renewal Agency is expected to rake in another $74 million. The Government is anticipating a profit - or "dividend" - of about $733 million over the next four years. This is a profit margin of about 44 per cent.

Khalid Ahmed, ACT Treasury's former policy director and an affordable housing advocate, has been rightly critical of these targets. He notes they have sent the price of home and land packages higher and higher.

This has a double whammy effect. People who pay more than they would have if the targets had been kept reasonable are then hit with an increased stamp duty assessment.

While the Government wins both ways, young people entering the market for the first time are the biggest losers.

The ACT Government is effectively the monopoly supplier of residential land in Canberra.

Mr Ahmed, who argues a more reasonable profit margin would be in the order of 20 per cent, says this is unsustainable.

This stands to reason given the difficulties successive ACT governments have had in broadening the ACT Government's income base by growing the private sector. The day will come when there is no longer any developable land to sell.

Canberrans are already moving across the border to dormitory suburbs such as Googong and Murrumbateman's Fairley because of the high costs. Once there they pay no rates or stamp duty to the ACT. The wider the price gap becomes between the ACT and those residential areas just across the boarder but still within easy reach, the more people will be attracted to settle there, generating further pressure on the ACT to provide services to those interstate commuters.

The Government's defence that it is using land sales revenue to support schools and hospitals is also of concern.

Asset sales income should not be used to cover recurrent expenditure. It's like selling your car to pay off your monthly credit card debt.

How will the ACT pay its way when it has no more land to sell but still needs to pay our police, nurses, teachers and the like?