Waka Kotahi director of regional relationships James Caygill said speed limits needed to reflect the type of road and their environment, and in this instance 100km/h is not safe.
Between 2011 and 2020 there were 747 crashes between Christchurch and Akaroa. Nine people were killed and 74 others were seriously injured.
"This is unacceptable. It's time to stop paying the road toll. We know that safer speeds will make a difference."
More information on the speed limit changes can be found here.
New lower speed limits have also been recommended for some side roads adjoining State Highway 75 on Banks Peninsula and in some rural townships.
The recommendations, in a Christchurch City Council report, will be considered by the Banks Peninsula Community Board at its meeting next week.
If accepted, they will be presented to the full council on June 9.
A map showing the affected roads can be found here.
It follows a joint speed limit review undertaken by the council and the NZTA.
The review looked at roads adjoining State Highway 75 which would benefit from a review should the speed limits change on SH75 as well as roads adjoining smaller settlements that would be suited to lower speed limits, a spokesperson said.
The lowered speeds will mainly affect low volume rural roads and those in small townships including Takamatua, Motukarara, Robinsons Bay, Kaituna, Little River, Cooptown, and Barrys Bay.
Council transport operations manager Stephen Wright said lowering the speed limits on local roads and townships could mean the difference between someone dying in a collision or walking away unharmed.
"Implementing safer speeds recognises these roads are becoming busier with people walking, riding, driving and cycling. This includes many vulnerable road users such as school children and the elderly.
"It also aligns these roads and townships with other speed reductions introduced across Banks Peninsula in 2021, which have been positively received by communities."