Ministry of Health figures show 3342 people were admitted to hospital with pneumonia in the four months to April - 168 more than the same period last year, and almost 1000 more than in 2005.
Year-on-year figures show the number of people hospitalised with pneumonia has consistently increased each yearsince 2005, from 10,540 cases to 14,393 in 2014.
Elderly were most susceptible.
Pneumonia killed 3225 New Zealanders between 2005-2011, the ministry revealed, but data for the number of deaths over the past 3½ years was not available.
Starship Children's Hospital paediatrician Dr Cameron Grant, an associate professor at Auckland University and expert on the illness, said he'd observed a spike in pneumonia sufferers this year. "We don't usually get the big pneumonia season until July, August, September, so everyone's feeling a little bit nervous about this winter," he said.
Grant said factors like damp housing and people not getting vaccinated were partly to blame.
"We're a malnourished population in that we've got high rates of obesity and high rates of micronutrient deficiency and both of those things are probably bad news from an infection point of view," he said.
"Smoking in the household remains a significant issue - it's one of the few places now where you're allowed to smoke and therefore children get it, and that can cause all sorts of problems."
