The ACT Government is powerless to force middle-class households out of government homes, despite thousands of families being on the waiting lists.

Instead, housing bureaucrats can only ask tenants on more than $80,000 per year to ''reconsider'' their continued presence in public housing.

But Housing Minister Joy Burch is considering legislative changes to send a message that public housing is not an unconditional home for life.

Research undertaken by Housing ACT of its tenants paying full market rent found 208 tenants in public housing were on household incomes of more than $80,000, including 43 tenants who declared income of more than $100,000 and three who earned more than $140,000.

The majority of the middle-class public tenants were between 40- and 70-years-old and had been in their tenancies for more than 10 years.

But a couple earning more than a combined $40,300 would be refused social housing if they applied today, on the grounds that they earned too much.

There are currently 2008 Canberra families waiting to get into the public housing system, with a standard, non-priority, application taking more than two years.

Another 1247 households are trying to transfer their public housing tenancy, with the average waiting time for a ''standard transfer'' 3½ years.

Ms Burch told The Canberra Times that the city's accommodation crisis had forced Housing ACT to adopt a model that put the neediest first.

''We've got close on 12,000 properties and we target those most in need, as we ought,'' the minister said.

''As people move into public housing with high needs, their lives change, all of our lives change.

''We now ask our tenants what their income is, over a couple of years, and if they can sustain paying market rents, they can pay market rent within the broader community market, because we continue to have people on our waiting lists.''

Ms Burch said that each case had to be considered on its own merits.

''Some could be on $80,000 but be a year off retirement age with very little assets put away, so you have to look at these things on a case-by-case basis. But you should not just be moving into public housing and thinking 'this is it'.

''I think we need to change the attitudes and the thinking that there is home ownership, private rental or public housing as the only product out there.''

The director of the ACT Council of Social Service, Roslyn Dundas, came out in favour of middle-class public-housing tenants.

''It is important to maintain a mix of people in social housing,'' Ms Dundas said. ''As targeting is narrowed, this can lead to greater stigmatisation of people in social housing. It is not that we would expect someone earning $80,000 get allocated a property over someone earning $15,000, all other things being equal. But if someone in public housing starts earning and then earning more, they shouldn't automatically be kicked out of their home - it becomes a disincentive.''