Running out of patience with Britney Spears, Kevin Federline's attorney on Friday said he plans to seek consequences.

Mark Vincent Kaplan, who represents Spears' ex-husband in their child custody case, said he would ask for sanctions against the pop star for calling in sick to her court-ordered deposition.

Spears didn't show up to testify at Kaplan's office Wednesday as scheduled, and Kaplan said later that her lawyers told him she wasn't feeling well. Spears was photographed later that day driving with a friend.

"This can be done with her active participation or without it," said Kaplan, who said he would file papers asking the court to impose sanctions on Spears before Jan. 23, the next scheduled court date.

A telephone call to Spears' attorneys was not immediately returned Friday.

Judges often impose monetary sanctions, including attorney fees, said Professor Charlotte Goldberg, who teaches family law at Loyola Law School.

"There is always the possibility of (holding Spears in) contempt of court," Goldberg said. "After a certain point, when it's repeated behavior, courts become skeptical about that kind of excuse."

Kaplan said Spears had missed at least three previously scheduled depositions "for various reasons," so he asked the court to order her to appear at his law offices to be deposed on Dec. 12.

Spears and Federline have been wrangling for months over custody of their sons, 2-year-old Sean Preston and 1-year-old Jayden James.

Federline has temporary custody of the children because Spears, who has limited visitation rights, has defied court orders. Attorneys for Spears and Federline, married in October 2004, have repeatedly been in court about custody since they split. Their divorce was final in July.