Figures released less than a month out from the delivery of the ACT budget for 2016-17 show the tax has brought in only $4.4 million – about $8 million short of what was predicted to be in the territory's coffers by this time.

The tax has not reached its predicted revenue since it replaced the "change of use" charge in 2011.

Over four years to June 2015 the tax raised $35 million – less than half the $79 million forecast in the budget papers.

The budget forecasts $17.6 million for the next financial year and more than $18 million in each of the following two years – but it is unlikely to get near this if the trend continues.

The constant high expectations each year for the tax leaves a hole in the budget that must be filled elsewhere.

The Canberra Liberals have previously said that, if elected in October, the party would halt the lease variation charges for development in the city and the town centres for four years.

Chief Minister and Treasurer Andrew Barr has described this as "crazy" and preferential treatment for wealthy property owners.

Wealthy or not, it will be the property owners and developers who will be the major players in the revitalisation of the vacant, aged buildings dotted around the territory.

Anything that is considered a disincentive to this must be examined, particularly when it is apparent the tax is not meeting expectations.

The most recent office market statistics put out by the Australian Property Council show vacancy is decreasing for the top A and B-grade buildings, while it is increasing for the lower-grade stock.

C-grade stock is now at its highest vacancy rate on record at 19.3 per cent and D-grade stock vacancy sits at 30 per cent – these buildings are the ones ripe for conversions.

If the territory is going to have any success in enlivening the city and town centres in the future it needs to revisit this tax in light of these new figures.