A man was due to appear in the Palmerston North District Court on Friday afternoon charged with inflicting serious injuries on an 11-month-old baby.
The 45-year-old Wanganui man was arrested on Thursday night after a six-week police investigation.
It's believed the boy suffered injuries - a fractured skull and two broken legs - in Opunake on 1 May but was not taken to a doctor until four days later.
Police say they will be opposing bail.