Eight people have died from complications of the flu in Canterbury this year

Medical Officer of Health, Doctor Cheryl Brunton, says the patients all had pre-existing conditions - before dying of complications from influenza.

She says flu-like illness rates and related hospital admissions remain above average for this time of year.

Brunton says those most at risk of being seriously ill or developing complications from influenza include people aged over 65 and pregnant women - who can still get vaccinated.

Flu-related illnesses cause about 400 deaths a year in New Zealand, accounting for 45-per cent of sick days each winter.