A 28-year-old man has been charged with assault with intent to injure and injuring with intent to cause grievous bodily harm in relation to the death of 30-year-old Jasmine Wilson.
He is due to appear in Whanganui District Court tomorrow.
It is the third arrest police have made as they continue to investigate Wilson's death.
She died in Wellington Hospital on August 2, two days after she was taken to Whanganui Hospital in a critical condition with non-accidental injuries.
Police have also arrested a 28-year-old woman and a 48-year-old man on a charge of perverting the course of justice.
The woman will appear in Whanganui District Court on Tuesday, August 27.
The man has already appeared in court.
Meanwhile, police are still appealing for anyone with information about Jasmine's death to come forward.
"Even if you think the information you have isn't significant, we still want to hear from you," it said in a statement.
Anyone who can help is urged to call Police on 105, or give information
anonymously by calling Crimestoppers on 0800 555 111.