The Tesla CEO had previously claimed the new technology presents a "fundamental risk to the existence of human civilisation" but now the Facebook founder has criticised Musk for these negative comments.
In a Facebook live session, Mark said: "I watched a recent interview with Elon Musk, and his largest fear for future was AI. What are your thoughts on AI, and how it could affect the world? I have pretty strong opinions on this. I'm really optimistic. I'm an optimistic person in general - I think you can build things and the world gets better.
"But, with AI especially. And I think that people who are naysayers and kind of try to drum up these doomsday scenarios are - I don't understand it. It's really negative and in some ways I actually think it's pretty irresponsible."
And Zuckerberg says the improvements could come before the end of the next decade.
He added: "If you think about just safety, and health, and keeping people safe, AI is already helping us basically diagnose disease better, match up drugs with people depending on what they're sick [with] so they can get treated better. So it's going to help a whole lot of people get treated, and get better healthcare than would have had access to it before."
Musk had previously called for regulation in the AI industry before "it's too late".
Speaking earlier this month, he said: "I have access to the very most cutting edge AI, and I think people should be really concerned about it ... [AI is] the greatest risk we face as a civilisation. AI's a rare case where we need to be proactive in regulation, instead of reactive. Because by the time we are reactive with AI regulation, it's too late.
"AI is a fundamental risk to the existence of human civilisation, in a way that car accidents, airplane crashes, faulty drugs, or bad food were not. I'm against overregulation for sure. But man, I think with we've got to get on that with AI, pronto."