The network is said to be unhappy with the pilot produced by Pushing Daisies creator Bryan Fuller - which cost a total of $10m (£6.2m) - according to The Hollywood Reporter.
Mockingbird Lane - which stars Eddie Izzard, Jerry O'Connell and Portia de Rossi - could now air as a one-off Halloween special in either 2012 or 2013.
It could also undergo reshoots and be repackaged as a made-for-TV movie for international buyers, be dropped entirely or redeveloped from scratch.
"It's a fluid situation, but none of the options is ideal, especially considering the promise that this thing had," a source is quoted as saying.
Bryan Fuller - who is also working on a Hannibal Lecter TV series for NBC - recently denied that NBC was close to axing Mockingbird Lane.
"[That rumour] was dead wrong," he wrote on his official Twitter account. "Stay tuned for updates!"
The original Munsters starred Fred Gwynne, Al Lewis and Butch Patrick and ran on CBS from September 24, 1964 to May 12, 1966.
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Watch the credits to the original Munsters below: