The Canterbury District Health Board has extended free flu vaccinations to include people aged under 18.
The vaccine is already free to those over 65, under 65-year-olds with a chronic health condition and pregnant women.
The DHB says extending the free vaccination to those under 18 is a New Zealand first and is being offered to protect a population vulnerable in the wake of recent earthquakes against flu.
The DHB says it is concerned that, because of the quakes, many people are living closely in houses that are more crowded and working and studying in improvised office spaces and classrooms.
Homes may also be colder this winter, increasing the impact of flu, it says.
The free flu jabs are available to Canterbury residents from 4 April until 31 July.