A march is taking place this afternoon to protest 500 new houses being built in the suburb of Raheny.
Clontarf GAA Club and Clontarf FC have both objected to the plans, which would deny them access to pitches in St. Paul's College.
The site at St. Paul's has six fields which are used for GAA, rugby and soccer.
Crekav Trading is seeking planning permission to build 104 houses and 432 apartments on the land, replacing the fields with a gym and two outdoor all-weather pitches.
However Clontarf GAA told the Irish Times that the loss of the pitches they use now would leave them "desperately short of playing facilities".