National has sought to allay voters' concerns about its plans to raise $5 billion to $7 billion through the partial sale of four energy companies and Air NZ by saying 85 to 95 per cent of the shares would go to New Zealand investors and no single shareholder will be able to own more than 10 per cent.
But One News last night said it had sought the advice on which the Government based its asset sales plan from ministers under the Official Information Act.
It had been denied, and then went to the Ombudsman to appeal the Government's decision.
While the Ombudsman chose not to have the information released, it revealed the Government's assurances were based largely on the views of ministerial employees and on informal discussions with finance industry figures.
One News reported that Treasury admitted it had not provided Minister of Finance Bill English with any advice about the workability of a 10 per cent shareholding cap.
"It looks like National has deceived New Zealand, tried to cover it up and been caught out," Labour leader Phil Goff said.
The Ombudsman, in upholding the Government's decision not to release the documents, said disclosing the information could affect the returns gained from the sales, in turn having a significant economic impact.