Adams, at a London news conference Thursday, said that if Ian Paisley's party would not implement the agreement aimed at ending sectarian violence in Northern Ireland then the peace process would have to go forward without them. The agreement has never been fully implemented.
Adams apparently intended to turn the tables on Paisley, the DUP leader, who has repeatedly demanded Sinn Fein's exclusion from a power-sharing role.
Adams said there was no possibility of Sinn Fein being excluded from the Northern Ireland assembly.
The DUP has described the Good Friday Agreement as "fatally flawed," and ran on an anti-agreement platform in the recent British elections.
Adams said there was no way forward but on the basis of the Good Friday Agreement. He said British Prime Minister Tony Blair, standing "shoulder to shoulder" with Irish Prime Minister Bertie Ahern, had to make that clear.