Canterbury principals say they've been left high and dry without the necessary support to care for kids with post-quake trauma.

Currently just seven full-time DHB staff cover the needs of 136 schools.

Principals are praising Labour's plans to fund extra mental health services in the region's primary and intermediate schools.

A Labour-led government would provide 80 extra mental health professionals at a cost of 10-million-dollars per year.

St Martin's School Principal Rob Callaghan said there are many children with increased levels of anxiety, and teachers can't meet their needs.

"Students have withdrawal, disengagement from their learning, aggression in the playground and even in the classroom."

He said without the adequate level of professional support, it is very much like putting a band-aid on a broken leg.