Based on an average classroom size of 27 pupils, schools across Otago have lost 34 classrooms (915 pupils) since 2004, and more than a quarter of the region's 146 schools have fewer than 50 pupils, March 2012 roll return figures show.
While school rolls have grown in Central Otago (by 109 pupils), the Lakes District (by 748 pupils) and the Taieri (by 184 pupils) during the past nine years, the overall number in the region has dropped 3%, from 30,467 pupils in 2004 to 29,552 pupils, this year.
The decline is largely due to significant drops in schools in Dunedin (1437 pupils), South Otago (179), West Otago (78) and North and East Otago (262).
Nationwide figures show school rolls have declined less than 1%, from 750,101 in 2004 to 743,654 in 2012.
In the past year alone, the declining school population in Dunedin has caused the closure or amalgamation of Forbury School, Macandrew Intermediate, Caversham School, College Street School and Calton Hill School.
Statistics New Zealand senior demographer Kim Dunstan believes the roll decline, particularly in Dunedin, was caused by a drop in the birth rate which began in the early 1990s. There were 1700 births per year on average in Dunedin around 1992, but the number had fallen to, and plateaued at, about 1300 per year since 2000, he said.
"If the numbers stay the same, school rolls should also plateau in the next four to five years.
"Projections indicate birth rates will stay at about 1300 per year."
Mr Dunstan said birth rates had been increasing in the Lakes and Central Otago area in the past 10 years, and school rolls had reflected that.
However, the picture was not so rosy in the Clutha and Waitaki areas, where birth numbers were projected to fall further.
Otago Secondary Principals' Association president and Dunstan High School principal Brent Russell said any downward trend in population in Otago was concerning, but the figures needed to be put in perspective. He said the figures covered a nine-year period and showed Dunedin lost an average 160 pupils per year across all primary, intermediate and secondary schools, while Otago as a whole lost 102 per year.
"In general terms, the quality of secondary education would not be affected. Less students may result in more competition between schools.
"In the secondary sector, less students does not necessarily mean closures or amalgamations of schools, but rather some schools would have fewer students," he said.
"The staffing that each school receives from the Ministry of Education is formula-based and is based on the number of enrolments."
Otago Primary Principals' Association president Brent Caldwell was unavailable yesterday.
Education Minister Hekia Parata was also unavailable for comment yesterday, but in February this year she said small schools in urban areas such as Dunedin were likely to come under increasing scrutiny during the next three years as the Ministry of Education tried to operate in a constrained fiscal environment.
A briefing from Treasury to the minister said easy savings available in the schooling system had been made, and funding constraints meant it would get harder to meet the costs arising from demographic change and capital works.
Ms Parata said increasing pupil-teacher ratios, and consolidation of the school network, could free up funding that could be used to support initiatives to enhance the quality of teaching.
There were some areas of declining population throughout New Zealand with schools operating well below capacity, she said.
"These are incredibly inefficient and money gets diverted away from the learner into property management." A Ministry of Education spokesman said yesterday the ministry monitored demographic projections and school rolls and worked with boards of trustees to manage individual responses to the needs of communities.
"In this way, education provision is flexible enough to respond to roll decline," he said.
