The plug has been pulled on Wellington's trolley buses, after 90 years of plying the capital's streets.

The wires that have criss-crossed the central city since 1924 will come down in 2017, and the trolley buses will be replaced, under a plan being put forward by Greater Wellington Regional Council.

There are 60 trolley buses in the city's fleet, which was upgraded at a cost of $27 million only seven years ago. They would go under the plan, as would the city's 218 other buses - all to be replaced by more modern vehicles, which have not been chosen yet.

Paul Swain, the council's public transport portfolio leader, said axing the trolleys was "a big call, but the correct one".

The extra costs associated with the wire network, coupled with the difficulty of changing the buses' routes, were the main factors in the decision, he said.

They also caused backlogs when they broke down, and they could not overtake.

The 50-year-old power system would need upgrading soon at a cost of "tens of millions of dollars", Mr Swain said, and maintaining the 160 kilometres of wires and 15 substations cost $6m a year. The one-off cost of dismantling the network would be cheaper.

The council's new public transport plan will change bus routes around the city, focusing services on north-south and east-west spines. There will be more frequent all-day services, but also the need for more passengers to change buses.

It also outlines ticketing plans and updates to the frequency of trains. The public will be able to have their say on the proposed changes next month.

The first trolley bus was introduced in 1924. Mr Swain acknow-ledged there was a lot of nostalgia around the network, but said a call had to be made. "They are less reliable overall, and they're more costly to run."

The Cable Car Company runs the overhead network, and chief executive Simon Fleisher said it was disappointing the trolleys would be stopping. "They're an iconic part of Wellington that we all know and love."

While sad to see trolleys go, the most important thing was getting the best public transport network for the city, he said.

NZ Bus owns the trolley buses, and chief executive Zane Fulljames said it was pointless deciding to get rid of them without deciding what would replace them. "A decision hasn't been made . . . There needs to be a solid plan in place from trolleys to the next piece of technology."

Options for the replacement fleet included hybrid, electric or modern diesel buses, but the council has not yet identified a preference.

Mr Fulljames said the existing trolley buses could be used until 2022. "Start planning for what next now, so we can actually start investing for what next now."

Wellington Mayor Celia Wade-Brown said ditching trolley buses was acceptable, provided there was a good replacement.

PDFs available to view:

Current Wellington City scheduled bus service network



Areas outside Wellington City: current and future scheduled bus service network



Future Wellington City scheduled bus service network



Rail Services – Current Services

From just one trackless tram

When Wellington's first trolley bus route opened in 1924, just one "trackless tram" ran between Hutt Road and Kaiwharawhara.

A more extensive trolley bus network began to emerge in 1949, with the introduction of a route to Roseneath via Oriental Parade.

Trolleys gradually replaced trams on other routes. From 1949 till 1964, the year of the capital's last tram, Wellington City Transport built up a fleet of 119 trolleys.

Until the mid-1950s they were painted silver and known as "silver ghosts" as they were so quiet. Then, they were painted red and fondly called the Big Reds. Wellington stayed with trolleys through the 70s.

New transport laws in the 1990s prompted the council to sell its transport system. Stagecoach took over in 1992, and repainted the trolley buses white with blue, orange and red stripes.