(1)  Where in a particular case the Minister is satisfied that the prescribed circumstances exist, he may authorise in writing a registered nurse or midwife to be in possession of and to supply restricted substances or narcotic substances or restricted substances or narcotic substances of a class specified in the authorisation, in such circumstances and subject to such conditions as may be so specified.

(2)  The Minister may at any time revoke an authorisation under subsection (1) or vary the class of restricted substances or narcotic substances to which such an authorisation relates or vary the circumstances in which, or the conditions subject to which, such an authorisation may be exercised.