The signature of Sir Edmund Hillary at Mid Canterbury's Double Hut may be a fake.
The Ashburton Guardian sent a photo of the recently rediscovered signature to handwriting expert Mike Maran, who found nine differences with a known signature example of the mountaineer.
"In my opinion there are too many differences between the hut signature and the actual signature," Mr Maran said.
He considered it was an attempted simulation by another author, and that there was "little indication" the signature on the hut wall was written by Sir Edmund Hillary.
The term "little indication" is used in a worldwide handwriting and document examiners' scale, ranking signature match possibilities from one to five, one being "conclusive" and five being "inconclusive".
"Little indication" ranks fourth, behind "probable" and "strong indication"..
But he said the assessment was made difficult by the fact the signature was signed on a vertical surface.
"When writing or signing anything for comparison purposes the wrists on your arm need to be supported on a flat stable surface, so there are no distortions.
"Basically, writing comes from the psycho motor zones in your brain and flows through your arm on to the writing instrument on to the paper."
As well, the photo of the hut signature was faded and he could not pick up some of the finer points, and over time signatures could change because of personal and emotional circumstances. The example he compared the signature to is from a later period in Sir Ed's life.
Sir Edmund Hillary's son Peter said while the signature could indeed be his father's, and it did look like "old fashioned writing", he agreed with Mr Maran "that it doesn't look like his signature".
But he also cited the difficulty of comparing a sample written on a vertical rough surface and believed the best way to indicate whether it might be his signature was to establish whether Sir Edmund could have been at Double Hut in 1951.
Methven Tramping Club committee member Lew Shaw, who was among a group who rediscovered the signature last year, believes the signature is authentic.
He said knowledge of it being in the hut went back decades. This was backed up by Mayfield mountaineer Bill Hood, who said he first heard of the signature there more than 20 years ago.
It had been similarly a part of local knowledge that Sir Ed climbed Mt Taylor in 1951.
But a climbing partner of Sir Ed's, Ed Cotter in Christchurch, thought the great New Zealand mountaineer would have been too busy in 1951 to climb Mt Taylor and stay in the hut.
Mr Cotter said that in January of that year, he and Sir Ed had been among a party climbing in the Tasman Glacier area.
When they finished that Sir Ed had to "urgently" get back to Auckland, to help out on the family's beekeeping farm.
In May of that year Mr Cotter and fellow mountaineers flew to Auckland to meet Sir Ed before they flew with him to Australia to take a boat to Ceylon to climb overseas. Sir Ed did not return to New Zealand that year.
"I find it hard to believe he came down here to do a straightforward climb in that area and I certainly have no record of it," Mr Cotter said.
He believed the Department of Conservation, which had renovated the hut in previous years, would be able to shed more light on the matter. It could not be contacted for comment.