This included adding hundreds of vans and other vehicles, as well as an extra plane, to get cards and presents delivered in time.
Even at busy times, it was "unusual" for items to go missing, an NZ Post spokeswoman said, with many items reported missing turning up later as they were delayed, rather than lost.
"Each year, New Zealand Post processes and delivers millions of letters and parcels. The
overwhelming majority of these are delivered to the right place and within our delivery targets."
The number of reports of missing items has decreased each year since 2012, which the spokeswoman said was in part due to a change in the way reports were classified and recorded.
The agency pared back its traditional letter-delivery service last year and moved to alternate day delivery for standard letters in urban areas.
If it was established an item had gone missing, customers could qualify for either cash compensation or product compensation, such as free stamps or courier bags.
The value of the missing item and in cases of international delivery, whether additional compensation cover had been purchased, affected the amount of compensation.
Incorrect or ambiguous addressing, "human error" in processing or delivering, and theft after delivery were common reasons items went missing, the spokeswoman said.
If NZ Post suspected theft happening in an area, the local delivery team was notified and asked to remain vigilant. After mail was delivered, theft became a matter for police.
In October, NZ Post reassured customers it took security "very seriously" after incidents which left people concerned for their mail.
Billie May Graham, 22, was sentenced on October 14 to six months home detention after stealing letters from mailboxes and using credit cards she found inside them to fund her methamphetamine addiction.
The day before, a Wellington postie was sacked and referred to the police after thousands of items were found to have been dumped instead of being delivered to addresses in Maupuia in the Miramar Peninsula.
The mail, which included a number of local body election voter packs, was delivered to its intended addresses with a with a letter of apology after it was discovered.
It wasn't the first time a postie was sacked for not delivering mail.
In February last year, a stash of almost 2000 items - amounting to around four week's of mail - was found at a postie's house. He was supposed to deliver the mail to homes in Helensville and Parakai in west Auckland.
The man had been taking it home each day, planning to deliver it the following day, but instead it piled up, NZ Post said at the time.
And in April 2013, Queenstown postie Philippa Lynette Lindsay apologised in court to her former employers and residents of the popular resort town for stealing more than 21,000 items of mail.
Over a period of 17 months Lindsay, who was supposed to deliver the mail to homes in Wakatipu, hoarded the mail at her house.
The letters included medical certificates, medical appointments and results, final demands for bill payments, invoices, and academic certificates, as well as letters to young children, birthday presents and gifts.
Police discovered the huge haul - of which 1577 items had been opened.
Lindsay was sentenced to one year and five months in prison, and ordered to pay $30,000 in NZ Post and $354 to affected residents in reparation.
Missing items, letters and parcels
Year 2012 2013 2014 2015 2016*
Number missing 51,887 49,603 47,184 46,558 42,035
Compensation in product 662 626 435 241 96
Value $8744 $7677 $4269 $2714 $1199
Compensation in cash 4120 4357 3707 4220 3487
Value $441,496 $463,164 $378,539 $439,071 $367,551
Source: NZ Post
*Until September 30
