Radio station The Edge has defended its decision to disqualify a transgender woman from a competition to win breast implants, after evidence of vote rigging came to light.

Host Jay-Jay Harvey is planning a breast reduction, and in a promotion the MediaWorks-owned station is "giving away her boobs" - awarding a listener a breast augmentation, chosen by a listener vote.

Hamilton transgender woman Dakota Hemmingson, 24, appeared to win with 62 percent of all votes. Otago woman Jordan Hill came second, with 26 percent.

But on Friday, The Edge announced Ms Hill was the winner - saying evidence of fraudulent voting came to light, disqualifying Ms Hemmingson.

"The Edge team was provided with evidence of irregular voting activity via our third party voting website, Apester… as such they were discounted and we exercised our right to exclude the relevant competitor from participation in the competition," said a spokesperson.

"We are really disappointed that the competition has been tainted by this, for what should be a really positive result for the deserving winner. With all valid entries taken into account, Jordan was the clear winner of this competition."

“We have been in contact with ​The Edge a​s we identified a large amount of fraudulent​ traffic ​in relation to one of the participants,” Apester said.

“​The Edge have thus chosen to ​exclude this participant, at their own discretion. Please note the poll has not been updated and still shows results with the fraudulent votes.”

Winner Ms Hill put her name forward after getting a double mastectomy when she found out she had an 87 percent risk of getting breast cancer. She said a breast enlargement would "make her feel like a woman again".

Ms Hemmingson says Ms Hill is "very brave and deserves implants", but claims she wasn't notified of any allegations of fraudulent activity.

"All I was told is about something someone had said and that it didn't disqualify me. That is the only mention of being disqualified throughout this process. I wasn't given any chance to remedy anything."

Ms Hemmingson says she entered the competition after being fired from a job for being transgender, and feeling "constantly attacked" over her appearance.

The station's decision to disqualify Ms Hemmingson has been condemned by many commentators on social networks.

Newshub.