For apartments with an unimproved land value of $75,000, the tax will nearly triple to $1210 a year. Apartment owners whose rental property has an unimproved land value of $150,000 will pay another $600 a year, with a total bill of $1570.

Land tax is paid on rental properties. It’s an extra tax on top of rates, so owners of rental properties face a double hit, with an average 10 per cent rates hike also coming from July 1.

The ACT government is changing the way it calculates land tax from July 1, to raise an extra $10 million a year. It is shifting a bigger burden on to owners of rental apartments and units, who currently pay much smaller amounts of land tax than people with rental houses because their unimproved land values are so small.

A spokesman for Treasurer Andrew Barr said the change would make land tax fairer and more evenly distributed, and ensure it no longer favoured owners of townhouses and units. At the moment, about 55 per cent of properties that were liable for land tax were units and townhouses, but the owners of these properties paid only 22 per cent of land tax, the spokesman said.

In contrast, houses made up 44 per cent of properties subject to land tax, but house owners paid 78 per cent of land tax.

About 36,800 properties are subject to land tax at the moment, of which 16,200 are houses and 20,600 are units.

The new system includes a fixed charge of $900 and new marginal rates.

The upshot is big increases for people with rental properties whose unimproved land values are below about $250,000. Above about $350,000, owners will welcome a reduction in their land tax.

For a property with an unimproved land value of $400,000, the land tax falls by about $470 a year. For a property with an unimproved land value of $500,000, the tax falls by just over $1000 a year.

The result, according to Mr Barr, is a reduction in land tax for 6500 houses, and an increase for nearly all units.

The move also ensured that "an appropriate level of land tax revenue is generated", as Canberra continued its program of "urban densification" with more apartments and units, especially in the Northbourne corridor.

Land tax is charged on all residential properties that are rented, and those owned by a corporation or trust. It was abolished on commercial properties in 2012.

Mr Barr's spokesman said the ACT was the only jurisdiction to treat rental properties separately, so each property received the benefit of the lower rates at the bottom. All other states aggregated the total land holdings before calculating tax.