Victoria Racing Club has said in a statement that the'Lover' singer pulled out due to a scheduling clash, with changes to her Asian promotional tour meaning Taylor couldn't travel out to Oz.
Animal rights group PETA has since released a letter thanking Taylor for 'pulling out' of the event.
WATCH: Taylor Swift to perform at Melbourne Cup
"Taylor Swift dumped the Melbourne Cup, and PETA couldn't be happier." PETA's Outreach and Partnerships Liaison Emily Rice said.
"The event is riddled with horse breakdowns and death and is linked to the bloody horse-slaughter industry, which PETA most recently exposed in South Korea. None of this cruelty is consistent with the kind person we know Taylor to be."
Despite the official position being a scheduling conflict, fans have taken to Twitter to praise Taylor for not performing at the controversial event.