Private schools expect the recession could continue to harm their rolls for another three years.
Private school rolls fell by nearly 750 students to just under 29,000 last year after a decade of steady growth.
Last year's decrease happened despite an overall increase in the number of children in the schools.
The Independent Schools of New Zealand says a further drop in private school student numbers is expected this year.
It expects the recession will continue to affect its members until as late as 2013.
Executive director Deborah James says some schools are considering applying for integration into the state system.
Government funding for private schools was increased by $10 million per year in last year's Budget.