The request came in the form of a petition Samuel D. Ingham III filed in Los Angeles Superior Court Tuesday evening.
Jamie Spears has been the conservator of both her person and estate since 2008. Montgomery has served as the singer's temporary conservator ever since the elder Spears stepped aside due to health issues in September 2019.
In the filing, obtained by CNN, Ingham cites an order filed on October 10, 2014 that determined Britney Spears had an "incapacity to consent to any form of medical treatment" as the reason why Montgomery should take over full conservatorship.
CNN reached out to Ingham on Wednesday asking him to elaborate on why the singer is unable to make medical decisions. Ingham stated that he "cannot comment on a pending case."
Jamie Spears' attorney Vivian Lee Thoreen had "no comment."
The filing asks that along with over seeing Spears' medical decisions, that Montgomery be able to "restrict and limit visitors by any means," except from meeting with Ingham. It also asks that Montgomery be able to "retain caretakers" and "security guards" for Spears.
The singer's father was first court-appointed as conservator of his daughter's estate, along with attorney Andrew Wallet, in 2008, following a series of personal issues that played out publicly for the singer. For most of that period, he also oversaw her health and medical decisions. Jamie Spears became the sole conservator of the singer's $60 million estate in 2019, following Wallet's resignation.
Ingham first filed to officially remove Jamie Spears as conservator last August. In November the judge ruled that Spears stay on as co-conservator of the estate but appointed Bessemer Trust to serve as co-conservator.
CNN has reached out to Bessemer Trust for comment.
"I love my daughter and I miss her very much," he said at the time. "When a family member needs special care and protection, families need to step up, as I have done for the last 12-plus years, to safeguard, protect and continue to love Britney unconditionally. I have and will continue to provide unwavering love and fierce protection against those with self-serving interests and those who seek to harm her or my family."
"[Jamie] would love nothing more than to see Britney not need a conservatorship," Thoreen said. "Whether or not there is an end to the conservatorship really depends on Britney. If she wants to end her conservatorship, she can file a petition to end it."
According to court documents obtained by CNN in December, Ingham said Britney would not perform again as long as her father remained in control of her fortune.
Although Britney has not publicly commented on the ongoing conservatorship battle, she did respond to recent speculation about whether she plans to perform again.
The next court hearing regarding the conservatorship is scheduled for April 27.