Lucinda Creighton's unveiled her new party Renua Ireland.
The former Fine Gael Minister has said it is an "open party" and has claimed abortion and other issues of conscience will have such open policy.
180 candidates have already declared - including founder of the Jack and Jill foundation Jonathan Irwin.
The party has said there are no circumstances in which they would go into Government with Sinn Féin.
Ms Creighton said: "I am a child of old politics, I have tried to change the system from within and I have concluded without any doubt that it is impossible.
"It is not capable of being renewed within the existing political party system.
"That is the reason that we are all here today, because we believe that it is essential that we renew our poilitics so that we don't repeat the mistakes of the past."