Communications Minister Steven Joyce says he is unable to release the Cabinet paper that sanctioned the Government's $1.35 billion ultrafast broadband investment initiative as some of the information it contains may be misconstrued to indicate bias on the part of the Government.

It is understood the Cabinet paper includes some information provided by Telecom about the viability of the flagship government initiative.

The Dominion Post requested the paper in September. The Office of the Ombudsmen is investigating whether to order its release.

Setting out his reasons for refusing to release the Cabinet paper, Mr Joyce told the Office of the Ombudsmen that doing so could prejudice negotiations over the UFB scheme.

"The paper includes detail of informal propositions and financial detail provided by potential partners for the initiative. Neither these propositions, nor the fact they had been asked for, is currently public information.

"Whereas this information was only requested of potential partners as illustrations for my Cabinet colleagues, there is a significant risk that its release may (incorrectly) indicate favouritism towards some potential partners."

He says the Cabinet paper also discusses some potential risks related to the initiative, the release of which could "undermine the Government's ability to maintain a strong negotiating position".

The Office of the Ombudsmen is investigating whether to order Mr Joyce to release a letter sent by Telecom chief executive Paul Reynolds in August last year that is believed to discuss Telecom's possible involvement in the UFB initiative.

Mr Joyce was advised by officials to respond to the letter by phone. Mr Joyce said records of what he said did not exist or could not be found.