Los Angeles Superior Court Judge Brenda Penny approved Spears hiring former federal prosecutor Mathew Rosengart, who called on Spears' father to immediately resign as her conservator.

"We will be moving promptly and aggressively for his removal," Rosengart said outside the courthouse on Wednesday.

"The question remains, why is he involved?"

Britney Spears, taking part in the hearing by phone, told the judge she approved of Rosengart after several conversations with him. She then asked to address the court, but asked that the courtroom be cleared.

As Rosengart began to argue for a private hearing, Spears interrupted him to say "I can talk with it open."

"I would like to charge my father with conservatorship abuse," she said, speaking so rapidly she was at times difficult for the court reporter and journalists in the courtroom to understand.

She said she wanted the conservatorship to end immediately but not if it required going through any more "stupid" evaluations.

"If this is not abuse, I don't know what is," Spears said as she described being denied things as basic as coffee, her driver's licence and her "hair vitamins" by the conservatorship.

James Spears would not be stepping down as Rosengart challenged, his lawyer Vivian Thoreen said in court, adding he has only ever had his daughter's best interests in mind.

Thoreen said Britney Spears had many inaccurate beliefs, among them that "her father is responsible for all the bad things that have happened to her."

"Whether it's misinformation, lack of correction, or being wrongly advised, I don't know," Thoreen said, emphasising that for nearly two years James Spears has had no say over his daughter's life choices, only her money.

Spears has been under court supervision, with her father and a team of lawyers controlling her life and finances, since February 2008. She was in the midst of a public meltdown at the time and her family sought the conservatorship for her protection.

Spears has had throughout the proceedings a court-appointed lawyer to represent her interests, Samuel Ingham III, but he resigned after a dramatic hearing three weeks ago in which the pop star told Penny: "I just want my life back."

Fans from the FreeBritney movement outside the courthouse cheered the decision to appoint Rosengart, then cheered Rosengart himself when he walked out.

The June 23 hearing was the first time Spears openly addressed the court, telling Penny she was being forced to take medication and use an intrauterine device for birth control, said she was not allowed to marry her boyfriend, and said she wanted to own her own money.

At that hearing, Spears had more measured criticism for Jodi Montgomery, the court-appointed professional who serves as conservator of her person, overseeing her life choices.

Montgomery denied that Britney Spears was prevented from marrying or forced to use birth control. She lashed back at James Spears, saying that Britney Spears has expressed no desire to oust her as she has with her father.

Montgomery said she is committed to staying on the job and is putting a care plan in place to help end the conservatorship, something she said James Spears has expressed no desire to do.

Australian Associated Press