The Attorney-General has raised concerns about aspects of a bill seeking to change the law on drugs.
The Government's Misuse of Drugs Amendment Bill would reclassify pseudoephedrine and ephedrine as Class B2 drugs, but Chris Finlayson says part of the legislation breaches the Bill of Rights Act.
The reclassification aims to make it more difficult for potential manufacturers of methamphetamine, also known as "P", to get hold of the key ingredients.
But Mr Finlayson says the bill changes the onus of proof by requiring a defendant found with drugs to prove they do not intend to use them for supply, which is inconsistent with the Bill of Rights.
The bill also expands the law around utensils used for administering drugs to include incomplete utensils.
That would mean, for example, that importing or supplying a metal cone for burning cannabis would become an offence.