KEY POINTS:
While many New Zealanders are still struggling to recall their four-digit postcodes, big businesses have an added incentive to commit them, if not to memory, at least to their databases.
NZ Post introduced the system in June, and automated mail sorters that depend on the new codes are being installed.
A survey by the allrealestate.co.nz website shows that more than a third of New Zealanders are still unsure what their postcode is.
But NZ Post's priority is bulk mailers such as Telecom, power companies and banks, who have been given a two-year grace period - until June 2008 - to upgrade their databases.
If they do not, they could lose out on their bulk mail discounts.
- NZPA