He emphasised his Government would not dilute its treaty obligations and he was "very open-minded" about what would happen to the clause after consultation.
Speaking at his annual Waitangi breakfast yesterday, Mr Key said the Government believed a treaty clause was needed for the companies in which minority stakes would be sold.
He said although the Government preferred a more specific clause, he would not rule out using a general treaty clause, such as section 9.
"But, and I make this point, we remain very open-minded about what that final clause might look like.
"In the end, in the spirit of the treaty we are going to engage in genuine dialogue and debate, and we won't rule out any options being on the table after this consultation period."
He said the reason the Government preferred a more specific clause was to prevent ambiguity, "not because the Government wants to walk away from its treaty obligations".
He said a draft copy of a consultation document which had recommended there be no treaty clause in the new legislation was the Treasury's view, and he had taken it out before the paper was released.
"That is because the Treasury's view on life, more often than not, is dictated by what delivers the greatest economic performance." The issue of section 9 has dominated at Waitangi, with protesters and the iwi leaders sending a strong message to National that they would not be happy it if did not also cover the mixed ownership model companies.
Maori Party co-leader Pita Sharples has also reiterated the party would walk out on National if the situation could not be resolved, and the party yesterday called on iwi leaders to challenge the asset sales in court using section 9.
Labour leader David Shearer said it was becoming increasingly untenable for the Maori Party to stay with the Government.
"I think it would be untenable for them to ask the Iwi Leaders Group to take legal action while they themselves stayed in a coalition agreement with National." Mana Party leader Hone Harawira said the Maori Party had urged Maori to oppose any moves not to include section 9, and he urged the iwi leaders to take legal action.
Sir Graham Latimer expects he has a fair chance of success in relation to his claim to stop pending asset sales.
The Maori Council president will today lodge a claim at the Waitangi Tribunal, asking it to stop the sales until the tribunal first considers claims to water.
Iwi leaders such as Tumu te Heuheu, Tuku Morgan, Sonny Tau and Haami Piripi said they did not support the action.
