Greyhounds, known as "galgos", are used in Spain for hunting, but when the end of the November–February hunting season comes around their owners often decide they have no further need for them.
Campaigners say many are just abandoned and often starve to death or die after being hit by cars.
In some cases hunters dispose of their greyhounds by hanging them from trees or throwing them down wells, or they torture poorly performing dogs by breaking their legs or burning them.
"For them they are not pets, they are tools just like a wrench is to a plumber, they have no affection for the greyhounds," Beatriz Marlasca, the president of BaasGalgo, an association dedicated to the rescue of abandoned greyhounds, told a news conference.
"We either stop this from above or else it will never end. We must eliminate the root of the problem starting by banning hunting with dogs," she added at the news conference attended by three other animal rights groups.
Marlasca's group alone finds homes for around 200 abandoned greyhounds a year in Spain, Belgium and the Netherlands.
"A ban on hunting with dogs, as already exists in other European nations, would be a measure that would avoid much suffering to all these animals," said Silvia Barquero, the vice president of Pacma, a small animal rights party.