The monitoring of paramilitary activity in Northern Ireland was conducted by the IMC up until 2011.
The PSNI has previously said it would support any move to set up such a body.
Lord Alderdice, who is also a former leader of the Alliance Party, said he did not think it would be appropriate for the commission to return now.
Talks will begin next week in Belfast in a bid to resolve the current crisis,  sparked by the murder of ex-IRA man Kevin McGuigan Sr.
Police believe that killing was in retaliation for the murder of former IRA commander Gerard Jock Davison in the Markets area of Belfast in May.
The Ulster Unionists withdrew from the executive after police said Provisional IRA members had a role in the killing.
"The current crisis is of a different order," Lord Alderdice told BBC Radio Ulster's Talkback programme.
"Even before the horrible murders of these two men, we were right on the edge of devolution being set aside.
"If somehow or another, magically, the issue of these two murders was taken out of the picture, we would still be in that position of crisis where the assembly, the executive, is about to be suspended or fold because there is no agreement on the governance of Northern Ireland.
"The IMC or any new IMC could not help that problem at all, it did not have a political mandate to try to get people to negotiate on the politics and the governance issue.
"I think it is maybe unwise for people to look back at a form of treatment that worked before and say: 'Oh well the symptoms are the same so the diagnosis is the same'."
The ex-chair of the Independent Monitoring Commission (IMC) has said he does not believe bringing it back would solve the latest Stormont crisis.