The parents association at Brookhouse Schools has protested as illegal a move by the school asking guardians to pay Sh45,000 for their children to be re-enrolled.
They said a committee had advised that they should not heed the call "as it amounts to a new contract and an attempt to undermine the pending petition determination".
In an escalation of one of the most dramatic fights between a school and its clients, the parents are required to pay and re-enroll the learners by Monday next week.
It was not clear Friday what would happen if one failed to pay, but an official said parents had misunderstood the request.
Parents moved to court in April over what they said was exorbitant charges for online learning.
They said the school was demanding upwards of Sh700,000 a term for online classes, which is the normal fee for class learning, yet other institutions had offered massive discounts.
The case is still pending in court.
The school's director, Mr John O'Connor, in a letter dated April 20, dismissed a section of parents who had demanded a reduction of school fees, saying many others were okay with the charges.
"While the school may not agree with some of the comments made in your letter, we move forward with a positive commitment to our whole school community in a spirit of mutual respect," said Mr O'connor.
"We are collecting the data of our students to know who are willing to enroll and continue with our lessons."