Christchurch's Halswell suburb is growing so fast the government has brought forward the opening of a new primary school by two years.

Education Minister Nikki Kaye says the $11 million Halswell West Primary School will now open in 2019 on the corner of Richmond Ave and Killarney Ave, near a new residential subdivision.

It will have an initial roll of 450 and will be capable of expanding to take 700 children.

Construction will begin early next year.