A woman has been convicted of stealing mail from New Zealand Post's Christchurch mail centre over a period of up to two years.
The 40-year-old was not an employee or a contractor but managed to get into the centre in Orchard Road after hours.
New Zealand Post processing and automation general manager Marie Watson said she did not know how much mail had been taken since 2020 because the woman destroyed some items.
"NZ Post acknowledges it is awful to be a victim of theft. We are disappointed with the actions of this offender, especially the impact it may have caused to our customers," she said.
"We wish to sincerely apologise to our customers."
Some mail had been recovered by police and would be returned to the sender where possible, Watson said.
"We are currently in the process of sorting through some of the mail items which have been recovered and contacting impacted customers. Where it is possible to identify the receiver or sender of the mail, then those items will be returned to them," she said.
NZ Post launched an independent investigation into the theft, has tightened security at the mail centre, and notified the Office of the Privacy Commissioner.
"We have reviewed our security procedures to ensure we are doing all we can to minimise the risk of this happening again in the future," Watson said.
"NZ Post takes delivering what people care about very seriously and we are extremely disappointed that our customers have been targeted in this way."
The woman will be sentenced in October on 12 charges, including using a document for pecuniary advantage, burglary and unlawfully opening postal articles.
NZ Post warned customers not to send cash, vouchers or active gift cards in the mail network and use a tracked courier service instead.