The government's revenue office hauled in the figure using penalties, interest and back-paid tax in a push to recover unpaid income.

Revenue officials detect missing land tax by comparing records with other government agencies, looking for landlords who tell the Australian Taxation Office about their rental income but fail to pay tax to the ACT government on their investment properties. Over the past year it has issued 1078 assessments for unpaid land tax.

In some cases detected in 2017-18, property owners had not paid land tax on their investments for several years.

Chief Minister Andrew Barr said it was disappointing some landlords were not doing the right thing, despite the government’s efforts to work with managing agents and tax advisers, and raise awareness of land tax.

"It is unfair that some taxpayers are seeking to avoid their land tax obligations while others are complying with our tax laws," he said.

"The $13 million we have recovered goes directly to funding the services and infrastructure all Canberrans rely on. When landlords don’t pay their taxes, it’s our community that loses out."

Some property owners had lodged appeals against the revenue office's assessments they had missed tax payments, a government spokeswoman said.

Land tax is payable on any property that is not the owner's principal place of residence, except in some circumstances. Significant penalties and interest apply for unpaid land tax, and the ACT government uses data-matching to detect non-compliance even several years after it occurred.