More than 20,000 trophy hunters are descending on Las Vegas this week to take part in a series of “pay to slay” auctions that have outraged animal rights activists.

The hunting jamboree, at which delegates will bid for the right to take part in 301 hunts that will eventually kill about 600 animals in 32 countries, is organised by Safari Club International (SCI), whose members include the notorious killer of Cecil the lion.

The four-day extravaganza at the Mandalay Bay hotel and convention centre on the Las Vegas Strip includes live music from country veteran Merle Haggard and Blood, Sweat & Tears.

The auction features an array of items including a white gold leopard broach – starting price $39,000 (£27,500) – and bullet gift certificates.

But the centrepiece of the event is unquestionably the auction of packages to hunt – and in some cases stuff – big game. Lots range from Iberian red deer and Pyrenean chamois to Australian water buffalo and African elephants.

The description of the 10-day Alaska Brown Bear and Black Bear hunt, which has a starting price of $75,150, reads: “This all-inclusive hunt is an outstanding option for hunters who want an all-in-one luxury hunting experience…in amazing areas boasting the highest density of bears in the world.”

US dentist Walter Palmer, who shot Cecil the lion, with another of his trophies

It adds: “Method of take is hunters’ choice.”

The Ultimate Hunters’ Market has been condemned by animal rights activists, amid a renewed focus on the ethics of big game hunting after SCI member and US dentist Walter Palmer killed Cecil in Zimbabwe last year.

Wendy Higgins, of Humane Society International said: “The auction site reads like a grotesque killing-for-kicks catalogue, in which the lives of the precious wildlife are sold to the highest bidder so that they can be slaughtered for fun.

“It is a tragic indictment on our society that, despite the global outrage over Cecil the Lion’s pointless killing, this scale of trophy hunting is still going on,” said Wendy Higgins, of Humane Society International.

League Against Cruel Sports chief executive Eduardo Goncalves added: “It beggars belief that there are still people who are excited by the prospect of slaughtering an animal for target practice and turning it into a trophy.”

The Safari Club International (SCI) is expected to raise more than $2.5 million from auctioning the mammal hunts alone, which have been provided from various hunt organisers.