"And power has gone up across the board ... and I think we'll see it again coming into winter."
In Wanganui, about 100 Energy Online customers experienced the largest increase in local prices over the 12 month period ($165).
Part of this rise was due to a $61 increase in Powerco lines charges.
Mr Simi said those worse affected by rising power costs were families with young children, single-income households and students.
Consumer NZ recommended customers "shop around" to ensure they receive the cheapest rates. People should compare plans across different power companies, chief executive Sue Chetwin said.
- APNZ
Average power price increases
Feb 2012 - Feb 2013
Region Price Increase
Southland $194.22
Northland $176.72
Otago $162.38
Christchurch $150.16
Tauranga $138.85
Auckland $127.73
Rotorua $115.24
Wairarapa $111.19
Hawkes Bay $110.82
Wellington $101.45
Wanganui $90.56
Waikato $89.87
Dunedin $79.49
National $121.32
Figures calculated by Powershop, sourced from Ministry of Business, Innovation and Employment.