In February, chief executive Tiwana Tibble wrote: "Our fallback position is to sell or demolish the waka in February 2012 and therefore exit from this investment whilst still having positive funds in the bank."
The paper says owning the waka will cost the iwi $135,000 a year. Tribal trust board chairman Grant Hawke said this was the estimated cost of storage and maintenance.
Sources say post-World Cup users of the waka will have to pay $25,000 to erect it, and another $25,000 to pull it down.
Mr Hawke said that was in line with what he had been told.
Ngati Whatua expects to know its revenue opportunities by the end of the year, and Mr Hawke said the tribe was looking at international options to hire the waka out.
China would be an example of a country where it could be used to cement a New Zealand relationship.
"If it gets too costly for the tribe ... I think we have to re-look at it again," Mr Hawke said.
The tribe did not answer questions put to it by the Weekend Herald about the "fallback" sale or demolition of the waka.
But the ongoing costs and unknown income prospects are causing anger in some quarters of the tribe.
Tribal member Joe Pihema said that scrapped or not, the waka project had "failed the people".
"The cost ... is not only the $135,000 a year for storage, but the lost opportunities to further our people through improved education, housing, cultural and health packages."
The Weekend Herald has also discovered an email from Herewini Te Koha, a top official of Te Puni Kokiri (the Ministry of Maori Development), who wrote to Auckland counterparts and tribal leaders about the political cost to Dr Sharples of supporting the waka project.
"The key issue is that the minister has cashed significant chips with Cabinet to get the Waka Maori concept approved, funding allocated and Ngati Whatua ownership accepted."
Dr Sharples said Mr Te Koha's turn of phrase did not reflect his views.
The Weekend Herald asked the minister if "cashing his chips" would have been worth it if the structure is demolished.
"This has not come up in any discussions between myself, Te Puni Kokiri or Ngati Whatua," he said.
Many approaches had been made by organisations wanting to use the waka after the Rugby World Cup, the minister said.
Mana Party leader Hone Harawira said Dr Sharples' "major contribution" to the tournament amounted to a temporary "bauble".
"The expenditure of $2 million on a plastic waka which will only be there for 11 days, cost $130,000 a year to store and $50,000 every time somebody wants to use it?
"That's what I call a colossal waste of money."
When the project was revealed in April, Labour MP Shane Jones likened the waka to plastic kitchenware, dubbing it the "tupperwaka" and a nauseating gift to a hapu.
