The number was substantially higher than the figure reported when Chief Minister Andrew Barr announced most households would have their rates reduced in 2020-21.

However, Mr Barr's office has insisted the figures were consistent with his public statements from the time, dismissing any suggestions it mislead Canberrans on a key cost-of-living measure ahead of October's ACT election.

Mr Barr used a major speech in June last year to grant homeowners a temporary reprieve from annual rates hikes, a policy designed to support households and inject money into the economy amid the COVID-19 downturn.

The announcement at Mr Barr's State of our Territory address was also widely seen as serving a political purpose, helping to neutralise the Canberra Liberals' main election promise of freezing residential rates for four years.

Rates would not increase for the "majority" of Canberrans in 2020-21, Mr Barr said, with the owners of about 110,000 homes - or about two-thirds of all properties - to pay less than the previous year after a $150 rebate was factored in.

The Barr government always acknowledged rates would increase for some households, either because their land value increased significantly or because they lived on an expensive block.

But the exact number of properties to be hit with a rate hike had been the subject of some confusion.

Mr Barr's office initially told The Canberra Times rates would increase for about 18,000 properties in 2020-21.

The following morning his office issued a revised number - 36,500.

But figures from ACT Treasury, published under freedom of information, showed the actual number was far higher - 60,295.

Mr Barr's office confirmed the figure was accurate when contacted by The Canberra Times.

It provided a further breakdown of the data, which showed 24,000 properties had been hit with an increase of between zero and 1 per cent. Rates rose between 1 and 5 per cent for about 34,000 properties, with the remainder rising by more than 5 per cent.

When asked to explain the discrepancies in the data on rate increases, Mr Barr's spokeswoman said numbers referenced in the chief minister and treasurer's public statements were consistent with the freshly published figures.

The spokeswoman said the government had consistently stated rates would fall for about 110,000 households after the $150 rebate was applied. The exact number was 110,691.

The sum of that figure and 60,295 equalled the exact number of households in the ACT, meaning rates bills either rose or fell for every ratepayer. Not a single rates bill was "frozen" at its 2019-20 level, according to the government.

Opposition leader Elizabeth Lee said it was disappointing Labor's "so-called rates relief" was not extended to more than 60,000 households.

"A rates hike for 60,000 households is almost double the number of households that was disclosed before the election," Ms Lee said.

"The Liberals have long campaigned for a fairer rates system, but for Labor and the Greens, unfair rates rises are just part of their DNA."

Mr Barr said at the time of the announcement the reprieve would be only temporary, with the start of the next phase of tax reform set to see rates rise an average of 3.75 per cent annually from next year.

But the government has left the door ajar to further tax relief, signalling it was prepared to adjust its approach if that was necessary to support households and protect jobs.