But the letter indicates consultation over all sales will take place this year, and a Government source confirmed this yesterday.
The Government will write by Wednesday to groups having a direct interest, and hold a series of hui for them.
The Herald understands the Government has written similar letters to about 30 iwi and hapu, detailing its objections to "shares plus" but seeking their views on the idea.
While the Government is extremely cool on the "shares plus" concept, the Herald understands it believes that consulting Maori on the idea will increase its chances of winning any legal challenge to its assets-sales plan by demonstrating its good faith.
The letter also says that "having regard to the role of the Maori Council in the Waitangi Tribunal proceedings, the Government also seeks the council's input into that consultation process".
Maori Council lawyer Donna Hall said the letter was being considered and would require "a very considered and detailed response".
"It's considered to be a document that needs expert advice and assistance. We are taking advice from the experts we called on the economics side in the hearing itself."
Meanwhile, Mana Party leader Hone Harawira was yesterday defending his use of derogatory language in relation to the Government's Maori MPs.
Reacting to Mr Key's comments on Wednesday that he would tell his MPs not to attend a national hui on water rights hosted by the Maori King, Mr Harawira said Mr Key "can tell his little house niggers what to do ... but the rest of us don't give a shit for him or his opinions!"
"Notice how John Key says none of his Maori MPs are allowed to go to the national Maori hui on water ... and two minutes later [Maori Party leaders] Tariana Turia and Pita Sharples say that they're not going. Not hard to see who's the real leader of the Maori Party!"
Mr Harawira later said the "house niggers" comment was not aimed at Mrs Turia and Dr Sharples.
Tuku Morgan, a spokesman for King Tuheitia, said he understood Dr Sharples would be at next Thursday's hui at Turangawaewae.
Speaking in Vladivostok, Russia, Mr Key said Mr Harawira should apologise for the comments.
He found them offensive and New Zealanders would find it offensive.
"I know it is Hone Harawira being Hone Harawira, but he owes them an apology.
"I know he is rent-a-quote at the best of times. But this is right out of line."
While there was freedom of speech in New Zealand people still had to explain their actions.
SHARES PLUS
* The Waitangi Tribunal has said that shares in power companies, with additional financial, governance or decision-making rights attached, are a possible means of redress for Maori rights over water.
* It says that any "shares plus" plan would have to be implemented before the partial asset sales.
* Otherwise, the sales could be a breach of the Treaty.
* The Government view is that virtually everything that can be done through "shares plus" can be done by other means after the sales.