5. Baseline of territorial sea---(1) Except as otherwise provided in
 section 6 of this Act, the baseline from which the breadth of the
 territorial sea of New Zealand is measured shall be the low-water mark
 along the coast of New Zealand, including the coast of all islands.

   (2) For the purposes of this section, a low-tide elevation that lies
 wholly or partly within the breadth of sea that would be territorial sea
 if all low-tide elevations were disregarded for the purpose of the
 measurement of the breadth of the territorial sea shall be treated as an
 island.