"I think it is absolutely appalling that the price differential between the overseas market and the product available onshore is so large. I'm appalled at it," Mr Duke said.
"At the end of the day, you've got freight, which is about 10 per cent, and you've got local GST, which these overseas purchases escape. The real difference between the two is about 35 per cent.
"I don't want to be accused of defending adidas because I don't like it either.
"I happen to believe that if the jersey was significantly cheaper, we would sell significantly more, and therefore the gross profit dollars that adidas would collect would be higher than they would be at the current wholesale price.
"If it were half the price you'd probably sell three times the volume."
Mr Duke would not reveal the cost price of the product, although Radio Sport reported it is understood to be around $105+GST, about the same price as the shirt can be purchased online from the United States.
Mr Duke said retailers are advised by adidas of what price to sell the product, but it is against the law for them to tell retailers what price to sell it for.
"At the end of the day, as a reseller not a brand owner, we are given a cost price and we've got to apply an appropriate selling price to the cost price we are given.
"I make as much gross margin out of an All Black jumper as I do out of an adidas t-shirt."
Mr Duke said he has spoken to adidas about his concerns.
"They are having conversations on this particular subject daily."
He said it was "possible" adidas would reduce the cost price, but "highly unlikely".
However some New Zealand retailers are defending the price difference.
Champions of the World director Gary Marshall, whose stores are an official seller, said New Zealand retailers could not sell the same volumes as overseas chains, and therefore paid more for the shirts.
"We're just applying our standard margins to [adidas'] product and selling it at recommended retail. What the [overseas chains] buy it for is not available to us.
"I was in our Wellington store on [Saturday] night and we traded until 10.30-11pm ... and I haven't had one person complain about that price."
A staff member at Champions of the World in downtown Auckland said the store had sold "hundreds" since the stock arrived on Saturday.
Yesterday, adidas New Zealand's country manager David Huggett said the cost disparity between New Zealand and overseas was in part due to currency fluctuations.
"The price we set in New Zealand is relative to the local market and the price they pay overseas is largely driven against currency fluctuation which has changed quite significantly over the last couple of years," he told Radio Sport.
All Blacks jersey prices:
USA online stores
RWC version - US$89.99 - NZD$103.80 (worldrugby.com)
Test version - US$79.99 - NZD$92.60 (worldrugby.com)
UK online stores
RWC version - 64.99pounds - NZD$122.20 (rugbystore.co.uk)
test version - 54.99pounds - NZD$107.70 (rugbystore.co.uk)
NZ stores
RWC version - $220 (Ryos in Wellington and Champions of the World)
Test version - $190 (Ryos in Wellington and Champions of the World)
*Overseas prices do not include postage and packing
