A vegan childcare worker says he is struggling to get over the trauma of eating ham on a pizza that was supposed to be plant-based.
Sydney man Patrick Hukins ordered Domino's on Monday, selecting a plant-based option.
But he quickly realised something was wrong when he started biting into the pizza.
"I had a horrible sinking feeling", he told Daily Mail Australia.
Hukins had soon discovered he had eaten ham, something which is strictly against his belief system.
He told Daily Mail Australia he feels "guilt", "shame" and "pain for the animal", acknowledging the consumption of meat "goes against my endeavours to reduce my environmental footprint".
The Sydney vegan claims he was repeatedly reassured it wasn't real ham, but soon fell ill after eating the whole pizza.
He said he "felt betrayed" by eating meat against his consent and feels the incident has "thrown me off as I feel my values".
A spokesman for Domino's Australia said they deeply regretted the error, and encouraged others to speak up if they came across any issues.
"We would like to publicly apologise to our customer.
"This was an inadvertent mistake, which will be used as a learning opportunity for our team members."
Domino's said it was one of the largest sellers of vegan food in Australia.
They offered Hukins a voucher, but it is understood the voucher would not cover the cost of a plant-based pizza.