A four-person NZ Post team will today start helping police to sort through thousands of undelivered letters and parcels which were destined for residents of the Fernhill area of Queenstown.

The mail, which was found at the home of a 32-year-old postie who has been charged with theft, is expected to be sent out within the next few weeks.

A NZ Post investigation into complaints of missing mail was launched a year ago, but was not until Friday that the company had gathered sufficient evidence to refer the matter to police.

NZ Post spokesman Michael Tull said an internal investigation at the local branch was launched in November last year and, despite several security measures being introduced, failed to resolve the issue. "It did not produce the effects wanted and there was a notable spike from August this year . . . so we got national security staff involved."

Mr Tull refused to comment on whether the postie was told of, or involved in the investigation, including whether or not she was asked about the missing mail.

The missing mail generated 101 official complaints to the company since January 2010 and another 21 complaints had been logged since the theft was publicly reported on Monday.

The NZ Post contractor, who has been granted interim name suppression, could face more charges including some which fall under the Postal Act.

The woman is due to appear in Queenstown District Court on Monday.

Any residents of the Fernhill area who believe they are missing mail should contact NZ Post customer service on 0800 501 501.

- © Fairfax NZ News