A lawyer says a new and honest approach will be taken when sentencing drug dealers

Meth dealers who can prove their addiction caused their drug offending could have their sentences cut by 30 percent.

Its part of a landmark judgment released by the Court of Appeal.

Christchurch lawyer James Rapley QC says the previous regime, which looked at the weight of meth to assess the person's penalty, wasn't working.

Rapley says defendants who have addiction problems and come from a low socioeconomic background - can now be taken into account.