The country's so-called Road to Zero strategy is yet to to bring down transport deaths.

Waka Kotahi is proposing slower state highway speed limits, saying it's the best short-term solution to fatal road crashes.

Over the next four weeks, the transport agency will ask the public about a plan to reduce some 100 kilometre-an-hour zones to 80, or even 60.

Green Party transport spokesperson Julie Anne Genter told Charlotte Cook that even more roads needed slower speeds.