38-45 Medical aids and appliances
(1) A supply is GST-free if:
(a) it is covered by Schedule 3 (medical aids and appliances), or specified in the regulations; and
(b) the thing supplied is specifically designed for people with an illness or disability, and is not widely used by people without an illness or disability.
(2) A supply is GST-free if the thing supplied is supplied as a spare part for, and is specifically designed as a spare part for, another thing the supply of which would be GST-free under subsection (1).
(3) However, a supply is not GST-free under subsection (1) or (2) if the supplier and the *recipient have agreed that the supply, or supplies of a kind that include that supply, not be treated as GST-free supplies.