The US singer had been slated to perform two songs from her latest album Lover at Flemington Racecourse on November 5.

But less than two weeks after the performance was announced, Swift pulled out citing scheduling problems.

"Changes to her Asian promo schedule have made it logistically impossible for her to be here," promoter Michael Gudinski said in a statement on Saturday.

It came after an intense backlash from animal activists, who call on social media for the star to say #NupToTheCup.

"The pressure on Taylor Swift to cancel her performance was significant. Her fans did not want to see her supporting animal abuse," Coalition for the Protection of Racehorses spokeswoman Kristin Leigh said, following Swift's about-turn.

"Whilst the reason being used by the racing industry is a scheduling mix up, it appears to us that she has responded to those calls.

"Taylor would certainly be much more aware of the cruel reality of horse racing than she was a few weeks ago."

Emily Rice from PETA said she "couldn't be happier" about the pop star's backflip.

"The event is riddled with horse breakdowns and death and is linked to the bloody horse-slaughter industry," she said.

"None of this cruelty is consistent with the kind person we know Taylor to be."

The Victoria Racing Club says the cancellation is disappointing and is offering refunds to people who purchased cup tickets after Swift's performance was announced on September 12.

The club says it will make an announcement about pre-Cup entertainment shortly.

But animal activists say any replacement artists can expect the same backlash.

"We will be keeping a close eye out for whether another artist is announced to perform at the day, which is widely becoming known as a national disgrace," Ms Leigh said.

Australian Associated Press