Holy Trinity CE (VA) Primary School said that at least 15 children in their reception class were absent from school with sickness and diarrhoea.
In a letter to parents today (Friday, October 2), headteacher Mrs Wray said the decision had been made to send home the whole class.
She said: "Unfortunately, we have 15 children in reception absent from school today with sickness and diarrhoea.
"We have consulted with Public Health England and they have advised us that the remaining children should return home this morning to minimise the risk of more children contracting this.
"Could you please make arrangements to collect your child from the main playground as soon as possible. If you are unable to collect your child until later in the day then please contact school.
"We would also like to remind all families that children must not return to school for at least 48 hours following their last episode of sickness and diarrhoea.
"We wish all those affected a speedy recovery."
It is understood that up to 20 children and one member of staff have been affected by the illness.