Prison guards interrupt Maxwell's sleep to make sure she is still breathing, despite her having no history of mental health issues or suicide attempts, the lawyer said.
Maxwell, a former British socialite, has pleaded not guilty to all the charges against her.
Writing to Manhattan federal judge Alison Nathan on Tuesday, Maxwell's attorney, Bobbi Sternheim, said her client faces tougher conditions than inmates convicted of murder or terrorism.
"Despite non-stop in-cell camera surveillance, Ms Maxwell's sleep is disrupted every 15 minutes when she is awakened by a flashlight to ascertain whether she is breathing," Ms Sternheim wrote in the letter.
She added Maxwell is essentially kept in solitary confinement and subject to frequent and invasive searches.
Requesting that judge Nathan intervene to improve her client's conditions, Ms Sternheim did not reference Epstein's 2019 suicide.
Epstein took his own life at New York city's Metropolitan Correctional Center on 10 August while awaiting trial on sex trafficking charges.
Two guards that were on duty the night Epstein died have been charged with falsifying records.
They are accused of failing to check on Epstein every 30 minutes and fabricating logs to give the appearance that they had done so.
Ms Sternheim's intervention came a day after prosecutors said Maxwell was last week placed in a coronavirus-related quarantine and banned from meeting her legal team.
She was asked to self-isolate after a member of prison staff working in her section of the jail tested positive for the virus.
In Tuesday's correspondence, Ms Sternheim also complained that Maxwell was not being given enough time to review documents related to her case to "prepare the defence of her life".
Prosecutors recently produced more than a million documents related to the case. They say 13 hours a day - more than any other prisoner - is enough time for Maxwell to review the papers.
Ms Sternheim also requested a jail warden reported directly to the judge and Maxwell's legal team about her "condition of detention", rather than relying on information from US Attorney’s Office for the Southern District of New York.
Judge Nathan ordered Ms Sternheim and prosecutors to meet and confer on the requests and asked for a status update within a week.
Maxwell was arrested in July this year, almost exactly a year after Epstein's charges.
She was found hiding at one of her properties in New Hampshire. She has been denied bail and her trial is scheduled for July 2021.