The Automobile Association says the results of a two-year review of the drugged driving regime are woefully inadequate.
The Ministry of Transport compiled an eight-page report on the topic which went to the Cabinet this year.
Much of it is background information and the case against moving to saliva testing.
It says overall the regime is working well, but police officers considered the process to be drawn out or too subjective.
The AA says the report does not address all the issues that should have been considered.
However, Associate Transport Minister Simon Bridges says the drugged driving regime is working and saliva testing won't be considered until it's more reliable.