ACT Chief Minister Andrew Barr is concerned the states get a better hearing from the federal government because they have greater numerical representation in parliament than the territories.

There are 12 senators for each state and two each for the territories.

The issue came the fore this week when Tasmanian independent senator Jacqui Lambie backed income tax cuts on the promise that Prime Minister Scott Morrison would consider waiving public housing debt held by the Tasmania government.

The ACT has a similar amount of housing debt - some of which is subject to an interest rate of 12 per cent - as well as a $1 billion loan from the commonwealth to cover the cost of the "Mr Fluffy" asbestos crisis.

"Our combined population in the ACT and Northern Territory is greater than the state of Tasmania, and yet we only have a fraction of their Senate representation," Mr Barr told Sky News on Friday.

"If there is to be any future expansion of the House of Representatives then a modest expansion of the Senate would best be delivered by some additional senators from the territories - possibly from two to four."

He said proposals on how to deal with the loans were now sitting with Treasurer Josh Frydenberg.

The "Mr Fluffy" loan could be refinanced on the global capital market at a lower interest rate without federal approval, but the housing loan is subject to "penalty and permission", Mr Barr said.

Australian Associated Press