'You people are sick': MAFS AU star Martha Kalifatidis defends plastic surgery spree, compares natural self to Shrek

One of the stars of Married at First Sight Australia (MAFS) has defended her decision to go under the knife - and compared her pre-surgery self to fictional ogre Shrek.

Martha Kalifatidis fronted up to online critics on Saturday (local time) after photos were unearthed from before she had a number of cosmetic procedures done.

Instagram comedy account @mafsfunny posted a photo of "Martha's glow up" - a side-by-side image contrasting a photo of younger Kalifatidis with a recent selfie. 

Images of her younger self reveal Kalifatidis used to look quite different, with a larger nose, thinner lips and smaller breasts.

The 30-year-old has admitted to having had a nose job, breast implants and fillers injected into her face.

The photo drew mocking comments from trolls, who criticised Kalifatidis for having surgery. But the reality star hit back.

"So I should just go through life looking like Shrek," she questioned, referring to the overweight, green-skinned character from the 2001 animated film.

She also responded to people who joked that if she has children with her onscreen husband Michael Brunelli - who has also had a nose job - the kids will have her "old features".

"Troll me all you like... but why do you wanna go and talk about my unborn children?" she wrote. "You people are sick! Draw the line!"

Kalifatidis has been frank about her enhanced appearance in previous interviews. In February, she told 9Honey she thinks moderation is key when it comes to surgery.

"I still have photos of what I looked like before and a lot of people can't tell the difference. It's minor," she said.

"It's about not overdoing everything, and doing everything understated, and not being aggressive when it comes to changing your appearance."