Bec Zacharia has announced that she will go through with the controversial 'Barbie waist' surgery in Bali.

The Married At First Sight star has flip-flopped on the idea, booking, then cancelling, then re-booking the procedure over the past week.  

'I know that I said I would make a decision by Thursday and I have,' the 35-year-old said in an Instagram video on Thursday. 

'I have thought about this long and hard. I've thought about whether this procedure is something I want, and I've decided that I do. So I will be going ahead with the procedure of rib contouring,' she continued. 

'I am booked in for Monday and I will be documenting my whole journey on my Instagram. It's a decision that I'm really happy with.'

Bec said she made her final choice after speaking with a friend and realising she was disappointed, not relieved, when she initially cancelled. 

'I want this, so I've made that decision for myself and I'm going ahead... My body my choice,' she said.   

Bec had earlier dramatically backed out of the risky cosmetic procedure earlier this week after she received a wave of extreme backlash.

Just days after it was revealed the reality star had travelled overseas to undergo the increasingly popular rib contouring operation, Bec made a shock last-minute decision to walk away moments before she was due to go under the knife.

Speaking on the MAFS Funny podcast, Bec admitted she arrived at the luxury Bali hospital fully prepared for surgery before questioning whether she was making the right decision.

'I walked in and I thought, "Am I ready? Is this what I want to do?"' Bec said. 

'I just think that I'm going to take a little bit of time to think about it a little bit more.'

Podcast host Josh Fox, who documented Bec's journey, revealed he was stunned when she contacted him shortly after arriving at the hospital to say she had changed her mind. 

Bec stressed that no one involved in organising the trip had pressured her into proceeding with the operation.

'The company that's brought me out here isn't pressuring me saying, "You've got to get it done." I have the full ability to make that decision as to whether or not it's something that aligns with me.'

The body-contouring procedure, which is not currently available in Australia, involves reshaping the lower floating ribs to create a dramatically smaller waist without removing the bones.

The surgery has exploded in popularity among influencers, with several women undergoing the operation during the same Bali trip.

The latest cosmetic trend has sparked fierce debate online, with many accusing influencers of promoting unrealistic beauty standards.

Former MAFS bride Domenica Calarco blasted the decision, writing: 'Call me Karen, but getting the most insecure women to go and permanently change their bodies like this while promoting it… shame shame shame.'

Fellow MAFS star Beck Zemek also weighed in, warning she had turned down countless offers of free cosmetic surgery since appearing on the show.

'If I said yes to the amount of free plastic surgery I've been offered since MAFS I would be botched by now,' she wrote.

'I don't believe you should do something you never had insecurities about before just because it is presented in front of you… Girls, you're breaking your rib cages.'