Wellington councillors have made refitting and strengthening the existing library their preference, rather than building a new one.
The building has been closed for over a year, after it was deemed earthquake-prone.
Cost estimates for a refit range from $90 million to $200 million, while a rebuild is expected to be up to 40 million dollars cheaper at between $90m and $160m.
At a meeting today, councillors voted unanimously to speed up work on the redesign.
Mayor Andy Foster said the council just wants to get the work done.
"What we've done over the last week is that we all said we want it done quicker. We want an expedited process and that is exactly what these new resolutions do," Foster said.
"They speed us up by something like six to nine months by doing the developed design alongside the planned consultation process."
The council will begin public consultation in a month, with the aim of starting construction in July next year.