National Measurement Act 1960

The regulations may prescribe unreliable methods of measurement of an article or utility or a class of articles or utilities.

If the regulations make provision under subsection (1):

the unreliable method of measurement must not be used in working out the amount of any tax (however described) payable by reference to measurement of the article or utility or an article or utility of that class; and

no contract, dealing or other transaction is to be made or entered into that requires the unreliable method of measurement to be used in measuring the article or utility or an article or utility of that class for the purpose of determining the consideration under that contract, dealing or transaction; and

to the extent that a contract is entered into requiring the unreliable method to be used for that purpose, the contract is null and void.