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).
As part of Wellington Urban Motorway's development from Thorndon to Te Aro, the tunnel was constructed and originally envisioned to have a parallel three-lane tunnel for southbound traffic (with the existing tunnel serving only northbound vehicles).