Nursery leaders have warned of "catastrophic" staff shortages as a result of new government rules on qualifications for practitioners.
From September, staff at early years childcare providers will only be able to take a Level 3 qualification in childcare if they hold at least a grade C in GCSE English and maths.
Without the qualification, staff will not count towards the legal ratios of staff member per child that nurseries are required to provide.
Alternative qualifications such as Functional Skills will not be considered adequate.
The Save our Early Years campaign says the policy is "turning away a workforce" and is "having a catastrophic impact" on the sector as employers cannot recruit enough staff.
Campaigners want the alternative qualifications to be accepted as meeting the requirement to take the Level 3.
Carol Medcalf, managing director of the Carol Jane Montessori School, said: "I strongly feel, and this is backed up by experience, that the GCSE requirement, especially in maths, is a huge barrier for many wonderful staff entering the profession, and they become unemployable, which is crazy."
She added: "I myself do not have a maths GCSE - yet I have run a highly respected, multi-award-winning, Ofsted outstanding nursery for over 25 years, and I manage to get the business figures right."
She added that her nursery kept in touch with children who attended and many had gone on to be lawyers and doctors - one alumnus is an actuary - who do not appear to have "suffered from my lack of maths GCSE".