She has been part of the 2019 edition of the TV reality show that originally had 21 contestants expected to be in a house for 99 days.
Scotland Yard said the 29-year-old had been granted unpaid leave for an “unrelated reason”.
Her earlier request to take part in the programme was denied, according to a Met statement.
A spokesman said “A PC, attached to the Met’s transformation command, requested permission to take part in a reality television entertainment show in Nigeria. Permission was not given.
“The Met is aware that the officer has since appeared on the show without authority.
“The Met does not support the officer’s appearance nor does she represent the Met whilst appearing on the show.”
Television channel Africa Magic however said Ms Kareem joined the show to “do societal good”.
She was recently reported to have allegedly had sex with another housemate.
Ms Kareem and seven other contestants are currently nominated for eviction and she is seeking votes of viewers to prolong her stay on the show.
Contestants are fighting for the coveted golden prize of $160k (N60 million) and the enviable title of Big Brother Naija House.
Source: Africafeeds.com. Except headline altered.