Gavin quit the project to build the Irish Sky Garden at the end of last year. The eye-shaped pink pod balancing 25m above pools, hornbeams and box, which won gold at last year's RHS Chelsea Flower Show, is to become a tourist attraction in Cork.
But the EUR2m project has been dogged by cost issues and Gavin told FTE Radio 1 host Marianne Finucane that he was embarrassed to be associated with the scheme.
Lord mayor of Cork Terry Shannon said he had confidence in the management team. The local authority was pressing ahead with the garden, with completion due by the middle of the year.
A spokeswoman for Gavin said he was unavailable for comment.