Cost of life in Christchurch ?

Hello! I'm a french student from france. In about a month i'll live in Christchurch for my PhD. My salary will be 40000 nzd / year tax free.

I was wondering if it will be enough to live in Christchurch?

I did read from some post that the cost of life was about 500 nzd / week in total ? What are your expanses per week?