If you're flying into Christchurch airport, the closest National car hire location to you is 30 Durey Rd, and they can be reached on +64 3 358 6554.
No, National does not currently offer pickup services from Christchurch airport (CHC). However, their nearest location is 30 Durey Rd which is approx. 0.785mi away from Christchurch airport and accessible by public transport.