The development means Waititi's long-in-development "Akira" adaptation will be put on hold indefinitely.
In "Thor Ragnarok", Waititi infused his distinct style of humour and music to the narrative. "There was a conscious effort to put every colour known to man and every weird piece of music... (we) just wanted to make this movie into a big lovable, funny fist and then punch the audience straight in the face," Waititi had said while promoting "Ragnarok" in Sydney.
In the 2017 film, Thor (Chris Hemsworth) reunited with fellow Avenger, Hulk (Mark Ruffalo), and the two go on a journey to save Asgard. The cast also included Cate Blanchett, Tom Hiddleston, Idris Elba, Jeff Goldblum, Tessa Thompson, Karl Urban and Anthony Hopkins.
The movie has registered $854 million in business at the worldwide box office.
Hemsworth is expected to be back as the God of Thunder in the new "Thor" film, though an official announcement is awaited.