Parliament's Speaker David Carter has rejected a Labour Party complaint that Solid Energy's acting chief executive deliberately misled a select committee in March.
Labour MP Clayton Cosgrove raised the matter with Mr Carter after he said Garry Diack was more forthcoming about his company's financial performance with media than to the Commerce Committee.
In a letter, the Speaker said no question of privilege was involved.
Mr Cosgrove does not accept that response and believes Mr Carter is protecting the Government.
He said it was an open and shut case, and Mr Carter has failed to show he is a neutral and non-partisan figure in Parliament.
Mr Cosgrove said it has made the select committee process a laughing stock.