New research shows around 400 New Zealanders are dying from flu-related illnesses, each year.

Otago University, Wellington, has estimated influenza associated deaths from 1990 to 2008.

Study co-author Professor Michael Baker says seasonal influenza is probably New Zealand's biggest single infectious disease killer.

"400 deaths a year, some of those could be prevented with vaccination for example. Ultimately we do need to find other ways of stopping this virus."