I use diclofenac sodium supp for my kid every 12 hours when high fever is that ok to be given over five days ?

No: Diclofenac is not approved in pediatric patients by FDA. We generally recommend Tylenol (acetaminophen) or Ibuprofen for fever in kids. If they appear ill along with the fever or if the fever lasting more than 2-3 days, they need to go to see a doctor. A common cold or viral illness don't cause high fever for more than 3 days.

Voltaren (diclofenac): As a pediatrician I don't recommend Voltarin for children under 12 years of age for fever, it is mostly used to relieve pain from chronic arthritis or acute pain after surgery, you should use acetaminophen or ibuprofen to control fever instead of diclofenac. Good luck