Sinn Féin housing spokesperson Eoin Ó Broin opposed a social housing development in his own constituency after surveying local residents for their views on the project.
The 28-home development on public land was opposed by a majority of residents polled in Mr Ó Broin's Dublin mid-west constituency.
Sinn Féin councillors presented the survey results to South Dublin County Council and asked to move the 28-home development to another site.
They suggested building between 10 and 15 bungalows for elderly downsizers on the original site.
"Given the strength of local opposition to the proposed council development, Sinn Féin believes that the development should not proceed as proposed," the party said in a submission signed by Mr Ó Broin and his Dáil colleague Mark Ward.
Council managers agreed to reduce homes on the development to 19 units but said it could not change the site.
In December, Sinn Féin asked for a vote on the development to be delayed to allow councillors more time to consider the project.
At a meeting this week, the party put forward an amendment asking for the development to be reduced from 19 to 14 - but this was rejected.
Sinn Féin supported the final vote on the project after its motion was defeated.
"It's truly galling to see Eoin Ó Broin delaying housing in his own back yard," said deputy mayor of South County Dublin David McManus
Mr McManus said Sinn Féin's proposal would delay the project for at least another six months.
Mr Ó Broin said the Fine Gael councillor is "on a campaign to deliberately misrepresent" Sinn Féin's policy on housing.
"The councillor has no knowledge of what's in the best interest of locals in the area," he claimed.