Researchers are preparing to carry out one of the largest clinical trials of a flu vaccine in the South Pacific.
About 7,500 men and women are required from Australia and New Zealand to test the effectiveness of a new vaccine designed to protect against influenza.
Three New Zealand clinics are participating in gathering information for a drug company, which has commissioned the research on an anonymous basis.
Professor Jim Reid of RMC Medical Research in Dunedin, which is one of the clinics involved, says investigators conducted a similarly-sized trial in 2008.
However, because it was a mild flu season, more subjects are needed this year.
Each year between 10% and 20% of New Zealanders are infected with influenza.