The people he was living with at the time found the mail - which was meant to be delivered in Papatoetoe in August - and handed it over to NZ Post.
The mail should have been delivered in late August by the postie, who worked for NZ Post for a few weeks.
Northern operations manager Mike Lewis said once the pile of about 3,000 items was discovered the man was dismissed.
Earlier this year, an NZ Post subcontractor in north-west Auckland lost his job after stockpiling nearly 2,000 items of mail at his home.
But Mr Lewis said such incidents were rare.
"This is an isolated incident - we deliver about 600 million items a year, so when these isolated incidents occur, we take them seriously and refer them through to police."
Mr Lewis said the mail had now been delivered with a letter of apology.
He said less than 10 percent of the mail had been opened.