Gadhimai, located in Bariyapur 100 km from Kathmandu, comes alive every five years when the mass slaughter is held. However, since 2009, there has been increasing pressure on the temple authorities to ban the wanton animal sacrifice.
The festival, which takes place in honour of the goddess of power Gadhimai and is attended by millions of people from across Nepal and India, is being celebrated on Tuesday and Wednesday.
Thousands have already arrived at the temple premises with their animals meant for sacrifice.
In August 2016, Nepal's Supreme Court directed the government to stop animal sacrifices at the Gadhimai temple fair.
In response, the Gadhimai Five-yearly Festival Main Committee has said that it will follow the court's order and has decided not to kill pigeons this year.
The mass slaughter is slated for Tuesday and Wednesday. The slaughter will begin after sacrificing seven animals - "mice, pigeons, chickens, ducks, pigs, and buffaloes."
The last festival saw an estimated 10,000 buffaloes slaughtered, along with thousands of other animals at the Gadhimai temple fair, which is considered the world's biggest sacrifice of animals at any one site.
The temple slaughterhouse presently houses 3,000 buffaloes, guarded by police and a wire fence, waiting to be slaughtered.
Journalists and the public are not allowed to enter or take photos, the Himalayan Post reported.
Five years ago, after protests by animal rights activists, numerous reports in the media had claimed that the Gadhimai Temple had banned all animal sacrifice. But the herd of buffaloes awaiting sacrifice at the slaughterhouse speaks another story.
Sacrificing animals, including buffaloes, goats, chickens, ducks and pigeons, has been a longstanding feature of the festival.
Mangal Chaudhary, the main priest at the temple, said the "auspicious date" to sacrifice buffaloes is Tuesday, while Wednesday is for other animals.
Anticipating protests, security has been beefed up around the temple, with 1,500 security personnel deployed. Around 70 closed-circuit cameras have been installed and security along the Nepal-India border has also been tightened, the daily reported.
The Animal Welfare Foundation, an animal rights organisation, has launched a campaign against the sacrifice. But the campaign has not really taken off, said Sneha Shrestha, chair of the foundation.
( With inputs from IANS )