The programme has won over critics and fans alike since its 2007 debut, but the funnymen were left reeling by their sudden fame.
They recently announced they will be taking a year-long break from the spotlight, but now Clement has sparked fears the Conchords will end for good, admitting "It very likely might not (return)."
He tells Reuters, "It could come back in a shorter season or like a special. We've got to write the series, but we've also got to write the songs, and just dividing your time into those two writing tasks is really tricky."
Nancy Lesser, a spokeswoman for America's HBO network, adds, "We've left their future entirely in their hands. We would love to have more, and we left an open door at HBO."