Labour Senator Aodhán Ó Ríordáin is mounting a legal challenge to planning permission for apartments in Howth.
He's leafleted residents and plans to hold a meeting on Monday to organise a judicial review.
Senator Ó Ríordáin says he has no problem with the Marlet Group building new homes, but says local fears are being ignored.
"I'm not opposing the development," he said. "What I am opposing is the scale and the overdevelopment of the site that will lead to potential subsidence."
"It'll affect lands and houses on Balscadden Road and Astagob Park to the rear of the development. I've been working with these residents for six months or more.
"The problem with the new legislation is that the council has been bypassed and the only recourse that residents have in terms of appealing the decision is to go to the High Court."
"We're all in favour of the development there but [what] we're not in favour of is 80,000 tonnes of material being moved from that site, 5,000 truckloads of material, and the effect that will have on existing properties around the site."
"While a development is welcome, the scale of the development is something that's going to threaten already existing homes," he said.
