"They're appropriate participants in here," Superior Court Commissioner Scott M. Gordon said of the request by KNBC-TV and People magazine.
Spears and Federline weren't present for the hearing. Gordon scheduled another hearing for Sept. 14 to give their attorneys time to make their case for keeping the documents under seal.
After the hearing, Federline attorney Mark Vincent Kaplan said the documents contain information about the schedules of the couple's children and other details that could put them in jeopardy.
"It would be best for the children that they not be exposed," Kaplan said.
He gave no specific examples of threats to the children.
Spears' divorce from Federline became official July 30.
Since February, Spears, 25, and Federline, 29, have shared joint custody of their sons, 22-month-old Sean Preston and 10-month-old Jayden James.
Kaplan said Federline is seeking additional custody, but declined to elaborate.