Judge Richard A. Posner also ruled that the firms must reveal details of their imminent merger to their rival, Bloomberg reports.
Posner's decision came in a patent lawsuit filed by the iPhone maker in 2010 against Motorola, which has since hit back with a counterclaim. The two firms have a series of back-to-back disputes lined up to be heard in the judge's court, the first of which is scheduled for June.
As Google's $12.5bn (£7.7bn) acquisition of Motorola grants the firm access to its extensive patent library, the search engine firm has been drawn into the dispute. However, Motorola argues that its soon-to-be-parent company is not a party to the lawsuit.
"Google's employees and documents are not within the 'possession, custody, or control' of Motorola, and Motorola cannot force Google to produce documents or witnesses over Google's objections," the phonemaker's lawyers stated.
Google, Motorola and Apple are yet to comment on Posner's latest ruling.
> Apple calls for revised patent licence rules