A national census of school and nursery pupils is due to take place on Thursday.
The government has insisted that only those attending are counted at nurseries, while schools are permitted to count all registered pupils, including those learning from home.
Official government guidance is for all nurseries is to stay open during the latest national coronavirus lockdown.
Brighton and Hove City Council went against this advice and closed all its nurseries on Thursday 7 January to all but vulnerable children and the children of key workers.
The council’s head of early years and family support Caroline Parker told a meeting of the Schools Forum yesterday that it would affect funding this term and next term.