The refusal comes just months after the Auditor-General found the NSW government needed to be more transparent about the controversial "unsolicited proposals" process via which the Ausgrid deal was done.

Premier Mike Baird and Treasurer Gladys Berejiklian announced last month the government had accepted an unsolicited proposal from a consortium of local pension funds, meaning it did not go to tender.

The proposal by Australian Super and IFM Investors for the 99-year lease of 50.4 per cent of Ausgrid was revealed in late September.

If followed the decision by federal Treasurer Scott Morrison to block bids in a tender for Ausgrid from Chinese government state-owned State Grid Corporation and Hong Kong-based company Cheung Kong Infrastructure on "national interest" grounds.

In March, a report by then acting auditor-general Tony Whitfield found "there needs to be greater transparency and public reporting on unsolicited proposals received by government".

"Unsolicited proposals warrant more disclosure as they pose a greater risk to value for money than procurements done through open, competitive and transparent processes," Mr Whitfield said.

"This could include aggregate information about why proposals are declined, as well as more extensive information about proposals that have progressed beyond the preliminary and strategic assessment stages."

Despite this, the Department of Premier and Cabinet has only published a one-page summary of the Ausgrid transaction process.

Among the controversial aspects of the Ausgrid decision was the claim the bid was "unique" – a requirement of the NSW government's unsolicited proposal guidelines.

Mr Baird said this criterion was satisfied because the pension fund consortium represented "100 per cent Australian ownership" and that a government steering committee formed to assess the bid had agreed.

There have also been accusations from the NSW opposition that not going to tender meant NSW received at least $1 billion less than might otherwise have been the case.

When the government accepted an unsolicited proposal by billionaire James Packer's Crown Resorts for a second Sydney casino licence, it published details from each stage of the process and a 10-page summary of the steering committee report.

Asked if it would release the same information for the Ausgrid transaction, a spokesman for the Department of Premier and Cabinet said it would not.

"Certain information concerning the unsolicited proposal will be commercial-in-confidence, subject to the requirements of cabinet confidentiality, or otherwise exempt from disclosure," he said.

"The Department of Premier and Cabinet does not propose to release further information about the proposal at this time."