The three-minute clip, posted to Facebook, shows Khanjani getting increasingly uncomfortable as Kirby grills her about revelations she and Bachelor star Jordan Mauger were intimate during their time on the show together.
Kirby finishes the interview by asking if her breasts are "real or fake".
"Oh, they're fake ... it'll be five years in September," she replies.
Kirby responds: "I would love to be the rebound boy. He's in for a treat."
On Facebook, some viewers took offence.
"The camera work is disgusting. It's an interview not a bikini photo shoot," wrote one commentator.
"This is really disappointing ... disrespectful," wrote another.
Another viewer got in touch with the Herald to say: "I am disgusted with how George FM has treated her and it is fair to say she deserves better."
Mediaworks has yet to reply to a request for comment.
The breakfast duo were recently fined $8000 by the Broadcasting Standards Authority, who upheld a complaint against George FM after they named and shamed two women as "do-nothing b***es" last year.
Mauger chose Verhoeven over Khanjani in Monday night's finale after a season in which 23 girls competed to win his heart.