Councillors voted to initiate an amendment to recode 57 and 59 Marri Road, Duncraig, and 20, 22 and 24 Kanangra Crescent, Greenwood, from R20 to R40 and restrict the land use and advertise it for 42 days.
A council document said the size and location of the lots would "create an ideal opportunity to provide this form of housing" in Duncraig and Greenwood.
The building currently on the Duncraig land is leased to the Department of Education (DoE), with part of it used by the Department of Health as a child health centre.
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READ NOWOnce the DoE has left the premises, the child health centre will be moved to the Carine Child Heath Centre on Beach Road in Duncraig once refurbished. The Greenwood land is vacant.
The City is considering the sale of both pieces of land.
Cr Brian Corr voted against both motions.
"One of the reasons we are selling land is because we deem it to have no use in the future," he said.
"In Greenwood, there is a community hall and a scouts hall at Calectasia Street near the Greenwood shops and this is the only other site on which we could, in the future, build any facility.
"We might regret selling this land and I don't think it's fair to say we have no use for it in the future. I think we don't know and it's best in that case to keep this land."