The DUP leader has said he would not trust the head of the North's decommissioning body, Gen John de Chastelain, if he were to report that IRA decommissioning had occurred.
Only the open destruction of republican weapons and the dismantling of paramilitary organisations could satisfy the public that decommissioning had occurred, the Rev Ian Paisley said.
He said Gen de Chastelain had told him that decommissioning would have to occur in secret.
"He made it perfectly clear that no one was going to know how it was going to be done, the general public would not even know the number of arms that would be destroyed. It would all be done in secret and they would have to accept his word for it.
"I wouldn't believe him and I couldn't believe him because what we need is a degree of trust from the ordinary people, who are under attack."
He defined decommissioning as: "The destruction of their arsenal of weapons and the destruction of the residue of those weapons." As importantly, he said, "is the issue of the dismantling of the paramilitary organisations and a confidence-building demonstration that they have moved away from violence".
Even after IRA decommissioning, Sinn Fein should not be admitted to government immediately, he said. "There has to be a period of time for people to believe that it is over and that people are holding to politics, and politics only."