There may be some off-peak disruption affecting services in the Wellington region on Tuesday and Wednesday, Metlink said.
It comes as drivers attend union meetings across the region.
Commuters are asked to plan ahead using the Metlink app or website, and look out for service alerts affecting usual routes.
The overall impact on the network was expected to be minimal, Metlink said.
On 30 April between 10.30am and 1.30pm, services 250, 251, 260, 261, 262, 280, 281 and 290 will be affected.
On 1 May between 10am and 1pm, services 2, 3, 4, 14, 18, 20, 21, 22, 33, 34 and 83 will be affected.
RNZ
