Britney Spears' father should step down immediately and without conditions from his role as conservator of her estate, the singer's lawyer says in court documents.
Mathew Rosengart accused Jamie Spears of trying to link his departure from his 13-year-long role with payment of some $US2 million ($A2.7 million) in fees to his lawyers and for experts handling the media.
"Britney Spears will not be extorted," Rosengart says in documents filed with Los Angeles Superior Court on Monday.
"Mr Spears' blatant attempt to barter (his) suspension and removal in exchange for approximately $2 million in payments, on top of the millions already reaped from Ms Spears's estate by Mr Spears and his associates, is a non-starter."
Jamie Spears said for the first time earlier this month that he would relinquish control of his daughter's $US60 million estate because he did not believe that a public battle would be in her best interests.
But he gave no date for his departure and said he first wanted to get the latest bills for work by his attorneys approved by the court. Under conservatorship rules, Britney Spears pays for all costs incurred by her and others.
"Having finally acknowledged that his time as conservator should end, Mr Spears is obligated to step down without condition and without seeking to extract anything further from his daughter. Indeed, Mr Spears should resign now and if he does not, this court must suspend him on September 29th," Rosengart said in the filing.
The next court hearing in the increasingly contentious case is set for September 29.
Jamie Spears has controlled much of his daughter's life since 2008 when she suffered a mental health breakdown. The Toxic pop star, now 39, has been trying for more than a year to remove her father from the conservatorship and has refused to perform again while he remains in place.
Jamie Spears has repeatedly said he has acted only in his daughter's interests, to rebuild her finances and protect her from people trying to exploit her.
Australian Associated Press