(1) This Act may be cited as the Public Works Amendment Act (No 4) 1987, and shall be read together with and deemed part of the Public Works Act 1981 (hereinafter referred to as the principal Act).

(2) This Act shall come into force on the 1st day of April 1988.

The powers conferred by—

• (a) Section 11(2) of the Public Works Amendment Act 1960 to amend an Order in Council made under section 11(1) of that Act; and

• (b) Section 18 of that Act to alter, by Order in Council, the irrigation charge—

(being powers continued in force pursuant to section 222(3) of the principal Act) may be exercised from time to time in respect of any part of an irrigation district after the expiration of 10 years from the date of the commencement of availability of a supply of water to that part of the district.