Hasan is acting as his own attorney. The appointed standby lawyers asked to limit their involvement because the Army psychiatrist appears to be seeking the death penalty.
The court-martial was expected to resume after being suspended for a day.
The court-martial is being held at Fort Hood, where Hasan admitted in opening statements he went on a shooting spree in November 2009 that left 13 people dead.
The U.S. military has not held an execution since 1961 although several soldiers are on death row.
Military judge Col. Tara Osborn denied the request, saying it was just a disagreement on strategy, the Austin (Texas) American-Statesman reported.
Hasan objected to the standby lawyers' contention he is seeking the death penalty.
The newspaper said the motion by the standby lawyers to limit their role was filed Tuesday, and may have contained protected information that should not have been revealed to prosecutors. But chief prosecutor Col. Mike Mulligan said no one on the prosecution side looked at the documents.