Ōpaheke had a population of 2,868 at the 2018 New Zealand census, an increase of 276 people (10.6%) since the 2013 census, and an increase of 315 people (12.3%) since the 2006 census. There were 903 households. There were 1,398 males and 1,473 females, giving a sex ratio of 0.95 males per female. The median age was 33.7 years, with 627 people (21.9%) aged under 15 years, 624 (21.8%) aged 15 to 29, 1,332 (46.4%) aged 30 to 64, and 285 (9.9%) aged 65 or older.