Overall, just 37 per cent of New Zealanders exercised enough to meet ministry guidelines, and more than a quarter (27 per cent) exercised less than once a week or not at all.
Sport Bay of Plenty recreation team leader Sonia Lynds said the statistics were "not surprising".
However, it was "never too late to start", she said.
"This is why we have designed things like the Play in the Bay programme, [providing] more things for people to have a go at."
The Play in the Bay programme, a calendar of "give it a go" style activities and events, was piloted last year and would begin next month, she said.
It was aimed at helping people to get active, have fun and try something new.
Each month was themed, with activities held all over the Bay of Plenty, for all ages, fitness levels and abilities.
Calendars would be available from next week.
"There will be lots of opportunities for people who are nervous and don't want to get involved in competitive sport, or who have just lost their confidence," Ms Lynds said.
The benefits of exercising were "endless", she added.
Southern Cross Health Society chief executive Peter Tynan said the high number of inactive people was a huge worry for the nation. "Regular physical activity can help to reduce the risk of chronic conditions such as cardiovascular diseases, cancers, obesity and diabetes. Preventative action through exercise can help to save lives and tax dollars," he said.
"There's a misconception that exercise equals an hour at the gym. While that's great if you can, just getting up at lunchtime and going for a brisk walk or running around at the park with the kids will have you nearing the recommended activity target. Your activity doesn't need to be done in blocks, it can be three 10-minute bursts of activity instead of 30 minutes," he said.