Britney Spears' father has lost his bid to become her sole conservator.

A judge overruled Jamie Spears' request at a hearing on Thursday, after he objected to the appointment of officials at the Bessemer Trust Co. as the co-conservators of the singer's estate.

At the hearing, Jamie's lawyer suggested a co-conservatorship would "improperly reduce" his client's "powers over his daughter's estate", Variety reported, but the judge opted to continue with the arrangement.

Britney's lawyer, who was also in court, insisted a new order is the best-case scenario for his client as it gives Jamie and Bessemer bosses "an equal division of responsibility, in the hopes that they would sit down and figure out together the best way to handle this complex estate".

"It's no secret that my client does not want her father as co-conservator, but we recognise that removal is a separate issue," the attorney said.

Some of the pop star's fans and members of the #FreeBritney movement turned up to the courthouse for the hearing, which was held just five days after the release of damning documentary Framing Britney Spears. The film examines the conservatorship.

Earlier this week, the Toxic singer's boyfriend Sam Asghari spoke out to attack her father, calling him a "d**k" and accusing him of trying to control their relationship.

The conservatorship has been in place now for 13 years.