It came into existence on 7 December 2021,[1] prior to the opening of the Transmission Gully Motorway, and consists of the former route of State Highway 1 between Mackays Crossing and Linden.

The route heads to the south-west and passes through Paekākāriki, before travelling along the Centennial Highway through to Pukerua Bay along a narrow strip of land between the Paekākāriki Escarpment and the Tasman Sea, shared with the North Island Main Trunk railway line.

The original route north of Wellington known as the Centennial Highway from Ngauranga to Paekākāriki was started in 1936 and opened on 4 November 1939.

In Porirua city, in the 1990s, the road was widened to four lanes and realigned to ease curves from just south of Pukerua Bay to Mana.

[2] The stretch along the coast between Paekākāriki and Pukerua Bay is prone to slips, part of the reason the inland route through Transmission Gully was preferred for greater resiliency to natural disasters.