Some Halifax residents are expressing shock over receiving an advertisement displaying full-frontal nudity in their mailbox.

The ad wasn’t in an envelope and it wasn’t sealed. Now Canada Post admits it should never have been delivered.

“I would think it should be sealed with a warning on it, if nothing else,” says one area resident.

The ad was delivered to mailboxes in a Halifax neighbourhood through Canada Post.

On the cover, the ad features a woman in a bikini and encourages the reader to peek inside to learn about a “secret formula that will make you irresistible to every woman.”

But, flip the page open and the woman appears nude inside the pamphlet.

“I would think it should be sealed with a warning on it, if nothing else,” says one local resident.

“Yeah, I feel like that would be extremely inappropriate,” says another.

Canada Post is apologizing to anyone offended by the mail.

In a statement released to CTV News, a spokesperson says:

“It did not meet our product requirements and should not been delivered. Unfortunately, while the bulk of the mailing was recalled prior to delivery, we did not catch every piece.”

“I don’t agree that nudity should be delivered through the mail unless it’s undercover, under wraps, and unless it’s being requested by a customer,” says Carole Woodhall, who has been delivering mail for Canada Post for 10 years.

CTV News called the 1-800-number listed on the ad. A woman named Karla answered. She says she doesn’t know anything about how the company gets its mailing lists.

“I answer the phone and I sell hundreds of products…all different kinds,” she told CTV News.

When asked what the products are used for, she hung up the phone.

In addition to a naked woman, the ad also includes graphic language.

Rev. Jennifer Power, a minister at a United Church in Bedford, is disturbed by the idea of children seeing the ad.

“We teach children that their body is a gift from God, and that your body is something to be cared for, to be respected. That teaches children something totally opposite,” says Power.

“I’m very surprised and I’m very disappointed in our national mail system.”

Canada Post says it has only received a few complaints about the ad but is investigating how it slipped through the mail.

A spokesperson admits it was a mistake and processes are under review in the hopes of avoiding a similar error in the future.

With files from CTV Atlantic's Kayla Hounsell