Known as the Great Northern Railway for its first few decades of life, the Waiau Branch was seen as part of a main line north but was ultimately superseded by a coastal route.

During the 1870s, significant debates motivated by regional interests took place regarding the most desirable route for a railway from Canterbury to the West Coast, Nelson, and Marlborough.

Construction halted once Culverden was reached, and it became the northern terminus for the main line along the east coast of the South Island.

One notable proposal at this time involved extending the line via Hanmer Springs to Tophouse, and then building two routes from there, one to Nelson and one down the Wairau River valley to Blenheim.

Trains sometimes had to be banked through Weka Pass, requiring an engine shed in Waikari, and locomotive depots were established in Waipara, Culverden, and Waiau.

The branch was dieselised in 1968, and at this stage, despite the relaxation of laws and removal of subsidies that had benefited rail, it was still necessary to run two trains daily.

Much of the line's formation is still visible, and a part of it has been used as a walkway in Waikari, though it does not connect with the Weka Pass Railway's terminus in the town.