T-rex race against 'cruel' Melbourne Cup

Animal rights protesters sporting inflatable Tyrannosaurus rex costumes have descended on Flemington calling for an end to horse racing.

Puzzled onlookers watched on as a group of dinosaurs holding signs that read 'Horse Racing Is Prehistoric' converged for a race on Monday ahead of Tuesday's Melbourne Cup.

People for the Ethical Treatment of Animals (PETA) along with the Coalition for the Protection of Racehorses (CPR) organised the protest to encourage a boycott of the race.

CPR says 139 racehorses died on Australian tracks in the past year, in addition to the thousands of horses that die every year off the track from racing-related injuries or are killed for not being profitable.

"The Melbourne Cup - and all other events that cause horses to sustain catastrophic injuries and even die in the name of greed - deserve to go extinct," PETA's Emily Rice said.

"Today's dinosaur dash proves you can have fun by cheering on willing participants who enjoy themselves. No one needs to suffer for entertainment."

CPR Campaign Director Elio Celotto urged people to say 'Nup to the Cup' this year.

"We are inviting people to boycott horse racing by saying 'Nup to the Cup' and joining one of these many events taking place across the country," Mr Celotto said.

More protests are being organised ahead of Tuesday's event, which will mark the first with full crowds since the COVID-19 pandemic.

Victoria Police said it would have a highly visible presence trackside at Flemington, in the Melbourne CBD, and at major entertainment precincts across the four race days.

Uniform and plain clothes officers will be focused on deterring anti-social behaviour.