"This flyer was one of a series of flyers conveying intentionally distressing and morally questionable messages, such as killing stray cats, lying to your loved ones, and committing adultery," wrote the art collective Vertical Submarine on their Facebook page.
The flyers had been part of an interactive art performance titled Eville, staged over two weekends of the Singapore Night Festival.
The collective said that the performances, which included satirical elements, was meant to "explore the theme of evilness and depict several acts of evil happening in our society."
"The flyers were one such device and this would have been clear if the exhibition had been viewed in its entirety, rather than looking at one flyer outside of its context," the artists explained.
The "kill stray cats" flyer was singled out by animal welfare groups such as the Cat Welfare Society, SPCA Singapore and Voices for Animals, who condemned the message.
"Artists have a civic responsibility and should not express such messages of cruelty under the guise of art. We find it difficult to understand how the advocacy of such heinous acts can ever be termed art or on what basis this flyer was included in the programming of the Night Festival this year," the Cat Welfare Society initially said on its Facebook page.
The group later updated their Facebook post to include an apology for having shown the offending flyer out of context.
"We apologise that our presentation of the information made the flier out to have been distributed in silo, without the context of the exhibition included," the Cat Welfare Society wrote. "This flier has, however, come out at a time when cat abuse cases have increased in frequency and it has hit a very raw nerve with the cat loving community."