Complaints from Wellington bus drivers who've been resorting to tampering with excessively loud on-board speakers.

One city bus company is threatening to turn security cameras onto drivers to stop them reducing the volume.

Tramways Union National President Gary Froggatt says the noisy announcements keep giving drivers a fright.

"The driver is concentrating at the front of the bus and the traffic. Then all of a sudden, a noise comes - abruptly in some cases - advertising material."

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