"There's a lot of people out there needing somewhere to live," she said.
"About 65 to 75 per cent of our clients would only be eligible for social housing due to rent affordability and personal history. I don't think selling off those houses is serving the community at all."
The surplus HNZC properties for sale are in Kaitaia, Kawakawa, Mangonui, Okaihau, Paihia and Rawene, with some being sold as relocatable houses.
Whangarei and Northland area manager Diane Te Nana said HNZ's intention is to provide housing more suitable to the changing demands of social housing tenants.
"Alongside new or re-development, selling - or divestment - is integral to how we manage our portfolio. We have always bought and sold houses in response to changing tenants' needs and demographics over time," Ms Te Nana said.
HNZ will retain 2261 houses in Northland and continues its programme to upgrade those houses, she said.
HNZ declined to give a combined value of the houses up for sale, citing commercial sensitivity. The organisation was also unable to provide the Northern Advocate with how much the previous 81 sales were worth.
The sales have been slammed by Green Party co-leader Metiria Turei, who said regions like Northland would bear the brunt of National's "disastrous" state house sale policy.
"It's particularly concerning to hear the Government is selling off more than 100 state houses in Northland and has plans for only nine new dwellings."