The tunnel was opened as part of the extension of the Wellington Urban Motorway through Thorndon to Te Aro and was originally envisaged to include a parallel three-lane tunnel exclusively for southbound traffic (with the existing tunnel built for northbound traffic only).
The tunnel was constructed as part of Wellington Urban Motorway's expansion from Thorndon to Te Aro, originally planned to have a parallel three-lane tunnel exclusively for southbound traffic (with the existing tunnel serving only northbound vehicles).