bus lane dilemma

Can you advise me on this dilemma?
Wellington has bus only (bikes forbidden) and bus lanes (bikes ok).
A couple of bus lanes lead into traffic signals, where there is a 'B" green light, which operates before the green light for other parallel lanes.
If I find myself in the bus lane, can I go on the green B, or do I need to wait (with a line of buses behind me) for the general green?


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This suggests bikes must wait: http://www.nzta.govt.nz/resources/roadcode/about-driving/giving-way-at-c...

Cycle, tram and bus signals

At some intersections there are special signals for cycles, trams and buses. Cycles, trams and buses can move when these signals are on, but all other vehicles must wait for the appropriate green traffic signal.

A contact at a city council advises me that the common sense approach would be for a cyclist to go on the green B, although the Road Code suggests otherwise.
A solution would be to add a bike symbol to the traffic light but really, let's just use common sense.

This appears to be correct. From the Road User Rule comes this snippet:

3.6 Traffic signals in form of T or B

(1) While a white T or a white B signal is displayed, a driver of a light rail vehicle (in the case of a white T) or a bus (in the case of a white B) facing the traffic signal may
  (a) travel straight ahead or turn right or turn left; or
  (b) turn right or turn left even though a traffic signal is displaying a red signal in the form of a disc.

Nothing here that also allows a bike to use it. So it would seem that, for cyclists to also be able to go, you need a cycle signal as well, e.g. here is an example from Christchurch:

Bus & Bike signals, Christchurch Bus & Bike signals, Christchurch

I suspect that this is not well known (e.g. I've heard people say that the "B" stands for "bus" or "bike"). For now at least, you need to get Wgtn CC to install some cycle signals.

A postscript to this: the 2011 Road User Amendment Rule now allows bikes (and motor bikes) to legally go on a "B" light as well.