Peter Robinson has hinted he could use a ministerial veto to prevent research on the collapsed peace and reconciliation centre at the Maze becoming public.
The First Minister suggested there could be an issue over whether publication would be in the public interest, and said he had still to discuss the report with Deputy First Minister Martin McGuinness.
The market research was conducted by commercial real estate company Colliers International, which has a base in Belfast, and in a ruling earlier this month the Information Commissioner said it should be published.
However, the top two Executive ministers have been at loggerheads over the Maze project after Mr Robinson withdrew support for it following growing opposition in the unionist community.
The DUP leader was responding to a question from Ulster Unionist leader Mike Nesbitt in the Assembly, who said he was "astonished" by his reply.
Mr Robinson argued: "It is not the case that everything that the Government does should be published and disclosed. In the public interest, we have to ensure that the Government can still operate effectively."
But Mr Nesbitt said: "Let's stop the bluster and let's see the market research."