More than 18,000 property owners are using the pensioners rebate scheme for rates, figures revealed in an answer to a question on notice in the ACT Legislative Assembly.

However the number of applications for rates deferrals on the basis of hardship have doubled on the same time last year, after the ACT government changed the formula for calculating rates on apartments.

Pensioner rebates are currently capped at $700 but Greens crossbencher Caroline Le Couteur signalled she would like to explore whether that could be raised.

"We've been concerned about rates for some time. While we do support the general move away from stamp duty, we think we have to implement it in a way that's long term sustainable for all the people in Canberra and it seems to us there's growing inequity in Canberra," Ms Le Couteur said.

"Most of us are doing okay but there's a significant number of us who aren't and we need to make sure the rates burden is as such people on modest incomes and particularly I've been concerned about people who are living in houses in Canberra on the aged pension, are they in a position where they can continue to do so long term in the future? As unimproved land values are going up, the rates burden is changing and we need to look at that."

The ACT has moved towards a more land-based taxation system off the back off the Henry review, which recommended abolishing stamp duty.

The tax reform began in 2012 and will eventually result in what the government says is a fairer, simpler and more efficient method of taxation.

However Ms Le Couteur acknowledged there was much short term pain being felt by ratepayers on the margins of society.

"I was talking to some people this morning who [have moved into] a small, new, affordable unit, and it's become unaffordable and rates is only a part of it , the other part of it is we don't have enough regulation around building defects and their body corporate levies have gone up for more than they've expected because there are defects in the building so they're being hit from both directions," Ms Le Couteur said.

Ms Le Couteur said the Greens were doing their own policy work to develop a solution to the cost of living crises but she stopped short of supporting an extension of this year's $100 rebate for unit owners affected by rate hikes.

"We have to do a lot more work on this but I would see any rebate should be much more targeted towards income rather than just willy nilly," Ms Le Couteur said.

"The government does need to have revenue, we're not trying to say the government should do a lot less and we should thus be able to reduce rates hugely, that's not where we're going, the government needs a decent income but we need to ensure the income is sourced equitably."