Yet, at the opposite end of the city at West Belconnen, a new Commonwealth-funded ACT study is underway to look at managing storm-water runoff in a proposed greenfield development, “Riverview’’, which includes a Murrumbidgee River corridor strategy.

Meanwhile, at the southern end the National Capital Authority is preparing a brief for the Commonwealth government on what the process would be for changing Canberra’s main plan, following Liberal senator Zed Seselja’s push for Tuggeranong’s expansion to revive the town centre .

Former National Capital Development Commission chief Tony Powell said a 1983 plan circulating in the latest discussions appeared to come from a publication about the territory’s open space system, and the future development areas did not refer to urban development.

Mr Powell said the shaded striped area west of the river was for rural activities.

Areas on the eastern side, near Point Hut Crossing and Pine Island, were part of Lanyon and Lambrigg pastoral holdings, and in the National Capital 1984 plan all that area was set aside for further investigation.

The whole corridor all the way down to Uriarra Crossing was meant to be an environmental-historical corridor because of early settlement that took place along the river.

Mr Powell said the NCDC didn’t want to go beyond a ridge line near existing Tuggeranong into river catchment areas because of problems including storm-water runoff.

“I wouldn’t begin to think about what it would cost to develop areas and stop overland flows and stop storm water going into the Murrumbidgee River. It would cost millions and millions.''

Mr Powell said he withdrew sections on the eastern side of the river from the Y-plan for development to avoid an endless fight with former minister Tom Uren and the Hawke Government.

Mr Powell said developing near the river at West Belconnen and into NSW, as proposed in the Riverview development, would be disastrous too.

"Once they allow that there will be no stopping it," he said. "You will get urban development all the way to Yass. It’s a real estate developer's dream to go down there."

Former Planning institute of Australia ACT president Hamish Sinclair said that, given enough money, technology and time would overcome constraints at Tuggeranong, but previous studies showed significant environmental factors.

The territory needed rural land for renewable energy and many other activities that were not residential-friendly.

The latest compact city policy suggested inner city growth was more effective than suburban expansion and the density of the town centres was more than capable of absorbing extra houses which Senator Seselja felt were needed.

“The quality of life, accessibility to recreation and retail and transport, proximity and benefits of inner-area transformation, such as the Southquay project, are far more likely to add to Tuggeranong’s economic sustainability than a growth node at Tharwa," Mr Sinclair said.

“In addition, urban intensification in the residential corridor between Tuggeranong and Erindale would benefit without the associated costs of new building infrastructure," Mr Sinclair said.