UPDATED 11.24am New Zealand Post won't say exactly what happened to more than 3000 items of mail that a postie failed to deliver.

A postie has been stood down after the mail, including 667 voting packs weren't delivered to 13 streets in the Wellington suburb of Maupuia over the past week.

MORE: Postie stood down after 3000 items of mail go undelivered

The postie is now facing a disciplinary process.

Chief Electoral Officer Warwick Lampp said he was only told about it at midday yesterday.

"It's fair to say I was a bit grumpy about it. I was disappointed it took so long for Post to get to the bottom of the issue and let me know, so I had to move pretty quickly to sort this issue out," he said.

"When they found the mail it was un-tampered, unopened, so it wasn't as if we had to reprint or do special votes, so all the voting documents were in tact and ready to be delivered, so that saved us quite a bit of time."

Wellington City Councillor Sarah Free said people had noticed their mail was missing, but because of the recent changes to deliveries, they weren't sure why.

She said people have told her it's hard to know when to expect mail as it's not arriving every day, or even at the same time.

Ms Free said it was council staff who actually noticed the fault and alerted NZ Post.

Mr Lampp said the voting papers are going to be delivered to all the residents by a courier this morning.

"Each person will get a separate courier delivery of their voter pack with an apology letter from New Zealand Post at the same time."