When he "went public" last September, Mr Stewardson said he was intrigued by Mr Tustin's research into the possible survival of descendants of 10 moose released in the area in 1910.
The retired farmer, who lived near Hikurangi, claimed he had kept the photos secret to avoid unleashing a frenzy of wild moose chases. He said he now wanted the photos to see the light of day.
"If I croak, the story's gone forever," he told the Northern Advocate.
Instead, his "story" has become one more fallacy, another false trail in the great Fiordland moose hunt.
Last year Mr Tustin said he was disappointed the photos came too late to be included in his 2010 book A (Nearly) Complete History of Moose in New Zealand.
The photos nevertheless caused a stir and Mr Tustin felt obliged to put the record straight.
"It makes no difference to anything I'm doing or have done, other than I feel I should erase the record if I can, in case someone else is now sucked in," he said. "However, I must say I'm disappointed he carried his story, knowing it was not true, to such great lengths and distances.
"Moose history has always been cloaked in secrecy - this could be viewed as another slant on it."