A postie has lost their job after they failed to deliver thousands of mail items.

As many as 2500 pieces of mail that should have been delivered in July and August to Te Atatu, Henderson and Te Atatu Peninsula were found at the worker's house, New Zealand Post's Mike Lewis says.

Lewis is the company's northern manager of customer service delivery and says the items are now being delivered to their rightful recipients, along with a letter explaining the delay.

"A postie has been dismissed following an internal investigation. We believe that they held onto this mail rather than delivering it."

None of the mail had been opened, he says.

"We apologise to customers for the inconvenience and upset this will have caused and can assure people that we are taking this very seriously."

Te Atatu Peninsula resident Michael Coote was one of the residents whose mail was delayed.

He got suspicious when he noticed he was not getting his weekly copy of The Economist consistently, missed out on early payment discounts on his power bill – and received an overdue notice on his water bill.

Lewis says he understands people may have concerns, especially when it comes to undelivered bills.

"If late fees have been incurred on bills as a result of this, we'd recommend people speak to the biller to explain the circumstances and ask for additional fees to be waived," Lewis says.

"Customers who have received a letter of explanation with a delayed bill could use the letter to support their request."