"You wouldn't be bouldering, you would be smouldering" - electrical associations criticise an alpine group for is poster image of a person hanging from a power line to promote indoor rock climbing.

Posters for an indoor rock climbing event showing a man hanging from a power line have been called stupid and dangerous by a national electricity body.

The posters for the National Indoor Bouldering Series - a type of rock climbing without ropes - feature a drawn silhouette of a person hanging by one arm from a power line above a cityscape.

The advertised competition is run by the New Zealand Alpine Club, who say they did not think the image would offend.

But Graeme Peters, chief executive of the Electricity Networks Association, said the Alpine Club's poster promoted reckless behaviour.

"I can't understand it. I looked at it and I just thought, that's crazy."

The poster was brought to his attention and a picture of it was sent to him, he said. The Electrical Engineers Association contacted the Alpine Club and passed their concerns on to him.

"Bouldering, I looked it up, has got nothing to do with power lines. The stupidity of representing that it [hanging from a power line] is okay … it could potentially lead other people to try it.

"And to me, if you did that, you wouldn't be bouldering, you would be smouldering.

"It's illegal and it's dangerous."

However, Alpine Club general manager Sam Newton said the image was simply "a heavily stylised cartoon image, that is clearly not based in reality".

"The poster … pictures a cartoon industrial scene where, in the background, a silhouetted character is seen training by performing one-armed pull-ups on a power line.

"The New Zealand Alpine Club takes safety seriously and does not condone one-arm pull-ups, little less using electrical infrastructure as training equipment.

"This poster had a total print run of 60 copies which were distributed to the indoor climbing gyms where the events are held. No suggestion that the events are held on power lines is made at all."

The Alpine Club were contacted on Wednesday by WorkSafe NZ and the Electrical Engineers Association who, Newton said, believed the poster was "reasonably likely to cause someone to break the law by climbing and swinging from the power lines".

The Alpine Club did not think the poster promoted that, but would work to address the misunderstanding, he said.

"It is our belief that the great job they [WorkSafe and the electricity associations] do posting ample warning signs and educating the public are sufficient that censoring this poster is unnecessary.

"However, if [they] believe that the image will increase the risk of people attempting one-armed pull-ups from power lines, we will defer to their expertise and remove the image from the National Indoor Bouldering Series website."