The polytechnic sector's financial results have sunk to a five-year low and the Tertiary Education Union is concerned about its future.
The Government says 18 polytechnics made a collective surplus of $31 million last year, their lowest since 2008.
Three recorded deficits, and most failed to reach the Government-mandated 3 percent surplus.
The Tertiary Education Union said institutions are struggling with falling enrolments and no increases to their government subsidies for three years.
But Tertiary Education Minister Steven Joyce said polytechnics have improved in recent years and are getting better results academically and financially.
