Performing in Sydney over the weekend, Black, a comedian and actor, presented bandmate Kyle Gass with a birthday cake and told him to make a wish; Gass responded by saying: "Don't miss Trump next time."
A video of the apparent reference to a rally shooting the day before, in which the former Republican president's ear was injured, traveled widely on social media.
"I was blindsided by what was said at the show on Sunday. I would never condone hate speech or encourage political violence in any form," Black said Tuesday on Instagram.
"After much reflection, I no longer feel it is appropriate to continue the Tenacious D tour, and all future creative plans are on hold. I am grateful to the fans for their support and understanding."
Gass similarly apologized on Instagram: "The line I improvised Sunday night in Sydney was highly inappropriate, dangerous and a terrible mistake."
"I don't condone violence in any kind, in any form, against anyone. What happened was a tragedy, and I'm incredibly sorry for my severe lack of judgement."
The comedy rockers formed their band in 1994 in Los Angeles. As an actor Black is known for roles including the voice of the character Po in the "Kung Fu Panda" movies.
He and Gass recently played a string of dates -- part of "The Spicy Meatball Tour" -- across the United States and Europe, and were scheduled to play a leg across Australia and New Zealand before a select few more stateside this fall.
