The Greens this week released a discussion paper calling for average unimproved value to be dumped as the basis of general rates, saying a system based on capital improved value would be fairer.

Such a system would mean that rates are higher for people with an expensive home and lower for people with a less expensive home, instead of the charge being tied to the value of just your land.

This would mean residents' rates bills would be more in line with their wealth, Greens crossbencher Caroline Le Couteur said.

However the Barr government rejected a similar proposal last year, after determining the transaction and ongoing implementation costs were too significant for a jurisdiction of the ACT's size.

A spokeswoman for Chief Minister Andrew Barr declined to release those costings, saying the proposal brought forward by the Greens was different to what the government had considered.

But Property Council of Australia ACT executive director Adina Cirson expressed grave reservations about the Greens' proposal in its current form.

“We welcome the fact that the ACT Greens are looking seriously at the issue of tax reform and how to address affordability in Canberra and strongly agree that it is time we took a good hard look at how the tax reform agenda is progressing," Ms Cirson said.

"Clearly we are in agreement with the Greens that the reform model and its progression is in urgent need of review - to see what the impacts have been for both residential or commercial property owners.

“However the Greens proposal in its current form is dangerous. Land tax is meant to be based on land value, not the market value of the whole property. It would deter people from doing any improvements to their property, and impact on building quality as people shift to using cheaper products to keep rateable costs down. This will impact all owners and the broader community."

Ms Cirson said the shift to a market value rates system would be in effect a "double tax".

"Home owners already pay tax on the materials and labour used for construction or renovations," Ms Cirson said.

“At a time where renewal is happening – and needed right across the city – applying a further disincentive to refurbish or improve properties in our city, by taxing based on property value and not just land value would bring things to a grinding halt to this renewal.”

Rates are increasing yearly in Canberra as the ACT government cuts stamp duty and other "inefficient" taxes, in line with the 20-year taxation reform that began in 2012.

Back then, the average rates bill for houses was $1406. This year, it's $2474.

However in the same period stamp duty on a $500,000 house has fallen from $20,500 to around $12,000.

Stamp duty on commercial property transactions of less than $1.5 million was fully abolished this year, and from next year first home buyers with a household income of less than $160,000 will also receive a waiver.

But last month, former territory Treasury policy director Dr Khalid Ahmed and economist Adrian Makeham-Kirchner said Mr Barr had broken his pledge that stamp duty tax reform would be "revenue-neutral".

They found growth in the territory's own-source revenue base has outpaced economic growth since the reform began with a nearly $400 million boom, and neither wages nor the territory's concessions system has kept pace.

The government rejected that analysis, saying the growth in own-source revenue was due to economic factors, rather than policy decisions.

But earlier in the year, analysis from the Housing Institute of Australia showed stamp duty revenue rose $80.4 million from $225.7 million to $306.1 million in the first five years of the reform, with cuts to conveyence duty failing to exceed bracket creep.

Again the govenrment pointed out the increase in stamp duty revenue wwas due to the strong property market, not policy decisions.

While Dr Ahmed concluded the brunt of tax increases had been borne by households, especially the 88,000 lowest income households, Ms Cirson said commercial property owners were now paying double the rates they did at the start of the reform.

"They are paying nine times more than residential owners and in effect paying the equivalent of stamp duty every single year - just over 5 per cent for properties over $600,000," Ms Cirson said.

"The brunt of the reforms are being deeply felt by local businesses and building owners but without the increase in rents by the same proportions, or the equivalent reductions in stamp duty.”

Ms Cirson said while the Property Council supported the abolition of stamp duty on the basis it was 50 per cent worse for the economy than company tax, their backing hinged on the reform being revenue neutral.

"We need to make sure [the tax reform] is meeting the objectives set out by the Quinlan review and that is not disproportionally impacting on affordability or deterring investment in the rental or office market," Ms Cirson said.

“All eyes are on Canberra as treasurers around the country are all looking to see if tax reform is the panacea that government’s believe it to be, and with the ACT the only one who has attempted this reform."