Energex lines-workers who work on Vector-owned Auckland power lines plan to take industrial action from May 1.
The Engineering, Printing and Manufacturing Union (EPMU) said the action would consist of an overtime ban and a callout and standby ban.
The union said Vector did not provide enough fundingfor contractor Energex to make a reasonable pay offer to its workers.
"To be honest, Energex is not the main player in this because it's Vector that has failed to invest in proper infrastructure and has failed to invest in the workforce needed to bring it up to scratch," said EPMU organiser Joe Gallagher.
He said the industrial action would put serious strain on Auckland's electrical infrastructure.
"Our members are already working around the clock to keep Auckland's ageing electrical network ticking over and we expect that the notified overtime and callout bans will result in serious supply issues.
"Our members can nearly double their wages just by crossing the Tasman because there is an international shortage of skilled lines-workers and Vector has known this for a long time but has refused to put up the cash to make sure its customers have the network they need," Mr Gallagher said.
