The sudden death of a young nurse after she was treated at Northam Hospital last month is being investigated by the West Australian coroner.

Tamika Ullrich, 23, died a day after presenting at the hospital, some 90km northeast of Perth, with a severe headache.

She was reportedly given an injection and pain killers, then sent home.

Health Minister Kim Hames said the matter - a sudden and unexpected death - had been referred to the coroner.

In 2010, an inquest was held into the death of 16-year-old Andrew Allan, who died a day after going to Northam Hospital in a weak, feverish condition, and struggling to breathe.

He was seen by a nurse, who believed he had gastroenteritis, and was eventually determined to have suffered swine flu and a bacterial infection.

He wasn't examined by a doctor.