Subject as hereinafter provided—
any building byelaw made by a local authority under this Part of this Act shall cease to have effect on the expiration of ten years from the date on which it was made;
any building byelaw made by a local authority under the corresponding provisions of any enactment repealed by this Act, or under any such enactment as amended or extended by a local Act, shall cease to have effect on the expiration of three years from the passing of this Act :
Provided that the Minister may by order extend the period during which any byelaw mentioned in this section is to remain in force.