The tunnel near the top of Mt Messenger first opened in 1916. It was a single lane with a sharp gothic peak. This was more than adequate for the amount and size of traffic that used the road at the time.
Previous to the tunnel being installed all traffic had to negotiate a hair pin bend. Many a passenger preferred to get out and walk rather than risk going off the edge of the precipice.
The peak was lost when the tunnel was expanded to two lanes in 1990. Further work will be done on this route with the possibility of this section of the road no longer used as SH3.