[1][2]: 137 A trolleybus was chosen over an extension to the Wellington tramway system because a large water main on the route precluded tram track construction.

[3][4][5] A second and more extensive network was approved in 1945, when it was decided to gradually replace trams with trolleybuses, preferred for being more manoeuvrable and more modern.

The building of Wellington Airport across the Rongotai isthmus required a deviation from the Coutts Street route that the trams had taken.

As late as 1984, a route was converted from diesel to electric operation, with the network reaching its maximum extent at around 50 kilometres.

[11][12] In November 2005, the trolleybus network was included in the sale of Stagecoach's New Zealand operations to Infratil.

[16][17] The published reasons included cost of infrastructure maintenance and upgrading, inflexibility of a wire linked network, plus slower speeds and less reliability than diesel buses.

Twyford claimed that the costs of paying out the demolition contracts would be far too high, which came under heavy criticism from Wellington residents and council members in support of the trolleys.

To the south, four routes ran to Newtown (1 and 3 via the Basin Reserve, 10 and 11 via Taranaki Street), with the 1 continuing south to Island Bay, the 10 terminating at Wellington Zoo, and the 3 and 11 turning east to Kilbirnie, where they met routes 2 and 6 via the bus tunnel and Hataitai.

[35][36][37] Using some components from the Volvos, they had a greater passenger capacity than previous trolleybuses, were low-floor and incorporated other improvements.

[39] In April 2016, NZ Bus announced that it would repower several buses, including all of its trolleybuses, with Wrightspeed gas-turbine hybrid powertrains.

[42] ^† manufactured under subcontract by Scammell Vehicles were initially painted silver, until an all red livery was adopted in 1958.