The panel, made up of European Commission officials, will be charged with playing devil's advocate to Monti's draft findings.
The move will concern Microsoft's competitors, who increasingly fear that the commission may issue a ruling that fails to prevent future abuses by the software maker.
One of the main issues in the case that Microsoft and the commission are farthest apart on is system.
Preliminary findings from the commission, which oversees EU competition regulation, indicated the bundling of Media Player in the Windows operating system gave Microsoft an unfair advantage over competitors.
Microsoft has, however, said it is unwilling to take the video and audio player out of Windows.
Microsoft competitors want the regulator to word its ruling to apply to the bundling of other middleware products as well as Media Player.
"If the EC rules that Microsoft should unbundle Media Player, I don't see Microsoft voluntarily unbundling other middleware from the operating system," said Thomas Vinje, a competition lawyer in the Brussels office of law firm Morrison & Foerster, which has represented some Microsoft competitors.
Vinje said the commission might hone its ruling on the Microsoft case to specific issues such as the Media Player question to avoid any potential appeal by Microsoft on the grounds that the ruling goes beyond the specific accusation made by the commission.
"If they do that, it leaves us in a situation where we will have to file new complaints about other products bundled into Microsoft's operating system, in which case it begs the question whether competition law is relevant to such a fast-moving industry."
Towards the end of last year the commission said it would still consider another offer of a settlement from Microsoft before it closed the case. Microsoft is believed to be close to submitting a final attempt at a settlement. Neither the company nor the commission would comment on that.