On Thursday, Dick Thompson, a WHO spokesman, confirmed Shangen Abdul Qader, a 15-year-old girl, from the northern Kurdish village of Raniya, had been a victim of the virulent H5N1 virus and a team of WHO experts were on their way to the country.
Samples from the girl's uncle, who also died while suffering severe respiratory difficulties, a bird flu symptom, had not yet reached the WHO-affiliated lab in Britain, he added.
Iraqi officials said earlier this week they were treating a total of 12 patients suspected of bird flu.
The two dead people lived in the largely autonomous northern Iraqi region of Kurdistan, near areas frequented by migrating birds and not far from the border with Turkey.
The WHO has confirmed 12 bird flu cases, including four fatalities, in Turkey last month.
While H5N1 mostly affects birds, it has infected 160 people, mainly in Asia, and now killed 86 people in seven countries, including the victim in Iraq.
Experts fear it could mutate to spread easily between humans and spark a pandemic that could kill millions.