The ACT government has rejected claims Chief Minister Andrew Barr has broken his pledge that his stamp duty reforms would be revenue-neutral, but admitted the overall tax burden has risen faster after reforms than it did before.
While the government rejected former ACT Treasury policy director Dr Khalid Ahmed's and economist Adrian Makeham-Kirchner's analysis, it also challenged the analysis and claimed some aspects were incorrect.
A Treasury spokeswoman also said the growth in territory own-source tax revenue since the 2012 reforms were due to economic factors, rather than policy decisions, as Dr Ahmed contends.
It comes as Opposition leader Alistair Coe said that irrespective of whether the rising tax burden on Canberrans was directly attributed to the reforms, or simply a broader 'tax hike', residents would still be 'gouged' by the increasing overall tax burden.
The pair's analysis contended the government increased its overall own-source tax revenue at a greater rate in the four years since the stamp duty reforms began at a rate faster than economic growth in the city.
The pair also claimed the rising burden, particularly in fixed portions of rates and other flat levies and taxes, was disproportionately affecting lower-income Canberrans, a point the government has not refuted, saying that such increases were "not targeted at any one section of the community".
A Treasury spokeswoman said the government remained "committed to a fairer, more sustainable and more accessible concessions program", but did not respond to Mr Makeham-Kirchener's central argument.
The spokeswoman also said stamp duty revenue rose about five per cent a year, mainly due to economic activity, and if the government had not begun reform, the rises would have been much greater.
She said the reforms meant that from 2011-12 to 2016-17, stamp duty revenue grew by 13.1 per cent a year nationally, while in the ACT it grew by an average of only 5.7 per cent a year over that period.
Mr Coe said he had not seen the complete analysis yet, but it reflected the Opposition's budget analysis in the past two years, particularly on the possibility the underlying budget position was in deficit, not surplus.
Mr Coe said that regardless of the mechanism by which government was increasing the total tax burden, it was still increasing at a faster rate than people, particularly those on low-incomes, could keep up with.
Mr Barr's spokeswoman also claimed the analysis did "not appear to be correct on a number of points" including Dr Ahmed's calculation that the government had received almost $400 million more since the reforms, than it would have had the overall tax burden grown at the same rate as the four years to 2012-13.
She said that as the service and infrastructure needs of our community continue to grow with Canberra’s population, the government had "called on other revenue lines to meet these needs".
"Changes to other taxes, charges and levies made in order to fund the services and infrastructure required by a rapidly growing population are separate to tax reform."
But Dr Ahmed said the government was using a different measure of gross state product in its analysis, but whatever measure was used, the result still showed the overall tax take was still out-pacing economic growth.
He also said the government's response confirmed his analysis that despite the intention of the reforms to be revenue-neutral, the government's key tax base, land, was experiencing greater taxation than merely the transfer amount.
The Treasury spokeswoman also said Dr Ahmed's claims the accounting treatment of large-scale renewable energy certificates overstated the overall budget position were incorrect, arguing it obtained independent accounting advice last fiscal year that supported the approach taken in the 2017-18 budget.
But Dr Ahmed said irrespective of the accounting treatment, the simple deferral of the timing of surrendering the certificates created an 'illusion' that it was bringing in revenue to government coffers when it was not.
Mr Coe said the certificates were written in as revenue in each year from 2017-18, but no actual cash had been exchanged, and if the government continued its policy to surrender them, it would not reap the touted benefits.
The government said its policy remained to surrender the certificates, but the surrender was delayed due to the National Energy Guarantee negotiations, and the government would reconsider the policy in 2020-21.