We are flying from Auckland to Beijing (China Southern Airlines) with a 2 hour stopover at CAN.

You need to collect your luggage, and check in again. The transfer will take place in the same terminal. By the way, CAN only has one terminal.

Here are the procedures: Flight Arrival- Quarantine & Inspection- Immigration- Baggage Claim- Customs- Transfer Procedures- Security Check- Waiting & Boarding. :)