A NSW father will face court after his nine-year-old girl was taken to hospital bruised and unresponsive after she ate food containing an illegal drug, police say.

The girl was taken to John Hunter Hospital in Newcastle on Monday, NSW Police said in a statement on Tuesday.

Doctors were told she had eaten food containing an illicit drug and may have been given non-prescribed medication.

She remains in hospital while forensic analysis determines what the girl consumed.

The child abuse squad arrested a 28-year-old man at a Raymond Terrace home on Monday night. Detectives will allege in court he assaulted the girl.

The father was charged with assault occasioning actual bodily harm and will appear at Raymond Terrace Local Court on Tuesday. Investigations are ongoing.