The promoters of Garth Brooks' Croke Park concerts have been told they need to apply for permission to hold them by next Wednesday.
People upset at the planned gigs have been invited to write to Dublin City Council, which could refuse to grant a licence.
Locals say Croke Park promised them it wouldn't hold any more than three concerts a year, without consulting them first.
A number of organisations, including the Croke Park Streets Committee hope the licence isn't granted.
They're calling on people from all over Dublin back their calls for the gigs to be called off.
Once the promoters apply for a licence, those opposed to the idea will have five weeks to contact Dublin City Council to tell them why they object.
