GMB Union has warned there are just three weeks to save Barnsley's nurseries from privatisation.
The union, along with early years workers and parents, want to stop Barnsley Council's plan to offload nurseries across six Family Hubs - which are essential resources in some of the most deprived communities in the town.
These hubs provide vital childcare, particularly for vulnerable children, and offer crucial support for families in need.
The privatisation plan will be debated at a full council on 27 February.
Councillors want to transfer control of the nurseries to private operators, but staff and parents are deeply concerned about the potential consequences for both the quality of care and the vital safeguarding opportunities that the facilities nurseries provide - especially when home intervention is necessary.
GMB Union is launching a campaign to oppose the proposal, including an online petition.
Parents and staff are also reaching out to local councillors and MPs, urging them to protect these essential services.
Vicky Austin, GMB Organiser, said:
“We understand the financial challenges facing the local authority, but we strongly urge them to reconsider these proposals.
"GMB met with the council and shared the concerns of our members, making it clear that we are committed to working together.
"However, we cannot stand by and let this decision be made without fighting to stop this potential privatisation, which goes against everything we stand for as a union.
"What Barnsley Council is proposing is outrageous. These nurseries provide exceptional care and support to some of the most vulnerable children in the most deprived areas of Barnsley.
“It is unacceptable that councillors are considering selling off these services to a private operator.
“Parents, staff, and GMB are united on this issue; we will not stand by while Labour councillors vote to dismantle vital services.”