(1) Where an Act of the Oireachtas, or a portion of any such Act, or an instrument made wholly or partly under any such Act, or a portion of any such instrument is expressed to come into operation on a particular day (whether such day is before or after the date of the passing of such Act or the making of such instrument and whether such day is named in such Act or instrument or is to be fixed or ascertained in any particular manner), such Act, portion of an Act, instrument, or portion of an instrument shall come into operation at the end of the day before such particular day.
(2) Every instrument made wholly or partly under an Act of the Oireachtas shall, unless the contrary intention is expressed in such instrument, be deemed to be in operation as from the end of the day before the day on which such instrument is made.