A whistleblower from Aurora Energy says there are poles almost 100 years old in use in the company's network in Dunedin.
Former staff member turned whistleblower Richard Healey said the company, that was the subject of an audit by WorkSafe, is utilising power poles dating back to the 1920s.
He said a pole at the intersection of Hillside Road and Burns Street was no longer fit for purpose.
"There's been 30 years of neglect here and here and this is the result."
In 2016 the pole was tested and found to be fine, but in 2017 it was red-tagged meaning it needed replacing. However, now the red tag had gone and it was now blue-tagged, suggesting that the pole was safe.
"But here's the thing, if you're going to have a risk-based strategy, you really need to accurately assess the risk. So here we've got a pole which was assessed as brand new three years ago, as critically damaged and in need of replacement one year ago and now back to fear for its design purpose," Mr Healey said.
Mr Healey said the pole was symptomatic of the company's concerning infrastructure.
It was one of more than 200 around the city which were well overdue for replacement, he said.
An Aurora spokesperson said replacements were prioritised on risk, mostly based on the pole's condition rather than age.
Aurora has not confirmed how many poles were red tagged and needed replacement, Chorus confirmed there were eight wooden poles which need replacement on its network.
Chorus' Christchurch field capability manager Lee Jansen said a number of tests were used to decide when a pole needed to be replaced and there was no set figure as to when a pole should be replaced.
"It depends on the vintage of the pole as well as how it was treated, and whether it was a softwood, hardwood, larch that sort of thing ... those could be anywhere from 20 to 40 years really."