Kmart has apologised and pulled an "offensive" child's bridal Halloween costume from its shelves after a petition was launched by an enraged Australian mother.

Melbourne woman Shannon B started an online petition on Monday, calling on the store to remove the miniature wedding dress from its shelves.

Aimed at children aged four to six years, the bridal costume included a dress and headband with veil.

"Each year, 12 million children - girls as young as 6 years old, the same size as this costume - are sold or married off by their family without their consent. That's one million child marriages per month!" Shannon wrote on Change.org.

"Child marriage means child abuse and torture in its worst forms - paedophilia, child rape, child slavery, child sex trafficking.

"Kmart - take this child bride costume off your shelves."

Despite the petition only receiving 179 signatures, the retail giant pulled the costumes on Tuesday afternoon.

"Kmart Australia regrets the decision to range the bride costume," a Kmart spokesperson told 7 News.

"It was not intended to cause offence and we sincerely apologise. We have made the decision to withdraw this product."

As of Wednesday morning, the costume is unavailable on the Kmart NZ website.

World Vision Australia's child rights advocate Mercy Jumo told 7 News Australia "anything that trivialises child marriage is disturbing".

"Children around the world dress up. They play," Jumo said.

"But children could rather be dressed up as lawyers, or as engineers, or as doctors. Are we affirming them to grow and to thrive? Are we protecting them as children?"

According to Unicef, gloablly, around 21 percent of young women are married as children. That's about 12 million girls aged under 18 every year.

Newshub.