(1) An action in tort does not lie against a person for anything that the person has done in the performance or purported performance of a function, or the exercise or purported exercise of a power, under this Act.

(2) The protection given by this section applies even though the thing done in the performance or purported performance of a function, or the exercise or purported exercise of a power, under this Act may have been capable of being done whether or not this Act had been enacted.

(3) This section does not relieve the Crown of any liability that it might have for the doing of anything by a person against whom this section provides that an action does not lie.

(4) In this section, a reference to the doing of anything includes a reference to the omission to do anything.