Event backer wants more information on when and where big marlin caught after test.
Details have emerged about how an angler allegedly failed a lie detector test after reeling in a huge marlin.
All four men on the fishing boat insist they caught the fish and should get the $48,000 prize, but the event promoter is so far standing firm.
David Baty from OddsOn Promotions said former police detective Dean Young, who says he hauled in the 136.6kg catch, failed the polygraph test "terribly".
Mr Baty said that Mr Young flunked two questions about where and when the marlin was caught.
OddsOn was contracted by the Hawkes Bay Sports Fishing Club to promote its Mega Fish competition over Waitangi weekend, with Mr Young's catch taking out first place.
But nearly two months later, Mr Young is yet to see his prize, an Isuzu utility vehicle worth $48,000.
He stands by his account. He had planned to sell the ute and split the winnings with the three other men on the boat, all of whom told NZME they were there and saw the lengthy battle with the marlin.
Mr Young's brother Lance and father Tony were adamant about the catch.
"I back my crew 200 per cent, not 100 per cent," Lance Young said, adding he was disgusted the prize hadn't been handed over. "We caught that fish fair and square."
The four men, all experienced fishermen, had signed affidavits saying so.
Mr Baty said the winning claim hadn't been declined, rather he requested more information from the club and his company was simply implementing a clause signed by the club.
"We have asked for the plotter used on the boat during the contest. Go Pro footage supplied shows Dean [Young] in a chair winding a reel, there is no footage of the marlin near the boat or being landed.
"The four people on the boat have all agreed to split the prize money four ways, they all have a vested interest in the outcome of the claim. The only person completely independent is the polygraph examiner, he is paid whether a person passes or fails an exam," Mr Baty said.
"No amount of pressure from your paper will change the fact we are investigating the [fishing club's] claim."
Mr Baty said he had paid out winning claims from the club in the past. He pointed to examples where polygraph testing was used in fishing competitions overseas, although club president Alex Smith said in his decades of angling he wasn't aware of it.
Mr Smith said the club vouched for the integrity of Mr Young and the others on his boat. "We need to look at what options we ... take next. We'll be seeking legal advice."
Promoter featured twice on Fair Go
David Baty has twice featured on consumer affairs TV show Fair Go.
Once was over a paper dart competition organised by the Papakura District Business Association in 1999. Auckland man Gavin Findlay was denied a $27,000 new car after throwing a dart 15m into a 30cm box on top of a car.
The throw was performed in front of a large crowd in a closed-off main street but Sports and Events Marketing, run by Mr Baty, said the effort was wind-assisted.
After months of wrangling, Mr Findlay was given the car in a good-will deal during filming of the Fair Go piece.
"The story on the paper dart had Niwa evidence that the winds gusted to over 25 knots that day," Mr Baty said.
"Mr Findlay negates to state that the original event was to be held inside a car dealer showroom - the car dealer got the local community club to run the event outdoors."
Mr Baty again featured on Fair Go a decade ago after water cooler customers raised questions about a promotion to win a return trip to Paris that ultimately had no winner.
"In 22 years we have [staged] thousands of promotions and paid out hundreds of claims," he said. "When we investigate a claim the first action is for the winner to cry foul and run to the media."