Previous rules meant Canberra’s rented homes attracted land tax, but vacant homes were exempt.

Under new rules, the tax exemption for those properties will be scrapped.

The new regime, however, contained a number of exemptions, including for houses undergoing renovations or deceased estates.

Government data for the past year shows an estimated 2500 dwellings – about 1.5 per cent of properties - in the ACT had been vacant for at least 12 months.

The laws passed the Assembly on Tuesday, despite the Canberra Liberals opposing the motion.

Opposition leader Alistair Coe labelled the changes as another "tax grab" by the government.

ACT Greens housing spokeswoman Caroline Le Couteur, who moved the motion last year, hailed the new laws as a win for housing affordability.

"Houses should not be sitting empty while an increasing number of Canberrans are struggling to find affordable housing," Ms Le Couteur said.

"A vacancy tax on vacant properties will go some way to freeing up some properties in what is an increasingly tight housing market.

"For too long both the ACT and Federal taxation systems have benefited investors over home owners, contributing to housing stress for a growing number of Canberrans."

Ms Le Couteur said the decision brought the ACT in line with other jurisdictions and hope the motion would be a small step towards improving housing affordability.

However, she said Commonwealth government must still act to address both negative gearing and the capital gains tax discount.

A Anglicare report recently set out a number of issues facing low-income earners in the Canberra property market, including the lack of stock affordable for those on the minimum wages.

Mr Coe said the Liberals had opposed the motion as the party believed would make Canberra more expensive.

"The Canberra Liberals are opposed to Andrew Barr’s latest property tax grab," Mr Coe said.

"His assault on property rights will drive up the cost of rent and deter investment in Canberra.

"By making Canberra more expensive, more families will be move across the border to NSW.

"The Labor-Greens government is already cashing in record revenue through exponential increases to rates and land taxes in addition to stamp duty."

Chief Minister Andrew Barr said the changes would help rebalance the housing market in favour of local buyers and encourage owners to rent out vacant properties.

"These changes are part of a number of measures introduced by the ACT Government to address housing affordability in Canberra, including our continued work to cut stamp duty.

"The foreign investor surcharge also brings the ACT into alignment with New South Wales, which introduced a land tax surcharge for foreign investors in 2017."