An electrical worker, who declined to be named, said it placed Unison in a monopolistic position. In the past, developers could get competitive quotes for projects.
He said few linesmen would accept a job offer from Unison.
"They've been in other contracting companies that have been let go by Unison. They're that bloody pissed off they're accepting job offers from Australia and around the country. That's skilled people and their wages leaving Hawke's Bay."
Established in 1920, Northpower has expanded from a Northland-owned and operated electricity distribution network to become one of the largest multi-utility contractors in New Zealand.
Unison Contracting Services is part of Unison Networks, which is owned by electricity account holders through a trust. Unison Networks also owns the electricity networks in Taupo and Rotorua. Profits are paid only to Hawke's Bay account holders, mainly in the Napier City Council and Hastings District Council areas.