Infrastructure investor Infratil says the Labour Party's portrayal of how much New Zealand electricity prices have gone up in the past three years is misleading.
A graph on Labour leader David Shearer's Facebook page - using Government data for 14 countries - shows New Zealand was one of only two where electricity prices rose between 2009 - 2012.
Bruce Harker, the head of Infratil's manager's energy team and TrustPower chairman, said the list of countries put forward by Labour omits Australia, where electricity prices have risen much more than in New Zealand.
Dr Harker said the comparisons being made are misleading and although if it's converted to New Zealand dollars it appears the electricity price has fallen in other countries, the reason for that is that the New Zealand dollar has appreciated so much over that period of time.
He said consumers in Britain, Denmark or Norway would say their prices have gone up 15% - 20% in that period.
Labour finance spokesperson David Parker, a former minister of energy, concedes power prices have gone up more in other countries than in New Zealand.
He said New Zealand prices for power from cheap hydro stations should not have risen as much as they have.
Dr Harker said other data on which Labour is basing its policy is also correct but says that the party doesn't appear to understand that, for example, back in the 1970s and 1980s, consumers weren't being charged anything to use electricity lines between their houses and the national grid.
He said residential prices have risen, but Labour had not taken the time to fully understand that and so had drawn the wrong conclusions.