Cr Jinty MacTavish raised concerns about the increase at Wednesday's annual plan meetings, but was reminded by Cr Fliss Butcher that residents of the more than 900 units had regularly said they did not want to be a burden on ratepayers.
The council has a policy the units pay for themselves.
Rents rose by 16% in 2008 and by about $9 a week in 2010, the latter increase to fund new units being built.
Cr Butcher said she understood the concerns, but it was important not to "muck around with the policy".
Council finance and corporate support general manager Athol Stephens said increases in insurance and maintenance costs were behind the proposed rent rises.
Cr Chris Staynes said the way this year's increases were calculated, more expensive, better-quality units would pay an extra 2.6%, while cheaper, lower-quality units would pay 3.9% more. He called for a report on ways to make the increase more equitable.
