Speaking at the MediaGuardian Edinburgh International Television Festival, Moffat told delegates: "As long as it was great and fantastic then yeah. But a film is on [for] 90 minutes and that is not as important as the series. But as long as it doesn't get in the way of the show we could do it."
His comments mean that there could be a follow-up to the two 1960s Doctor Who movies: Doctor Who and the Daleks, and Daleks - Invasion Earth 2150AD. Both of these films starred Peter Cushing as the Doctor - a part he never played for television.
Moffat's remarks also chime with comments made by BBC Fiction controller Jane Tranter, who also refused to rule out a movie spin off when asked by MediaGuardian.co.uk last year. "I would not rule out a film version of Doctor Who, no," she said.
Moffat also revealed that Steven Spielberg was a fan of the show. When he had to pull out of his writing commitments for Spielberg's Tintin film trilogy to take on his new job, Spielberg told him that "the world would be a poorer place without Doctor Who".
During his Edinburgh session Moffat also called on the press to stop print spoilers about the show's plot.
"Shut up, just shut up. It is easy to find out what's going on with the show. We virtually publish the scripts and we film in public," he said. "But in giving things away you become that bore in the pub who delivers the punchline of a joke a second before it is delivered."
He revealed that he planned to stay quiet about his plans for the show - he takes over for series five, to be filmed next year and broadcast in 2010 - to avoid spoilers.
Moffat also said that the Doctor would remain youthful and that casting an older actor, like William Hartnell, the first Doctor, was unlikely.
"The show is really tough for a superfit David Tennant so you might kill somebody who takes on the role in their 60s. For Doctor Who to turn into an old man you'd be pissed off," he added.
"Even William Hartnell had trouble back then, he was often ill and he forgot his lines. I think the Doctor will always be about 40."
Moffat has written a number of the most critically-acclaimed episodes of the revived show - The Empty Child/The Doctor Dances, The Girl in the Fireplace, Blink and Silence in the Library/Forest of the Dead.
He replaces Russell T Davies, the key creative figure behind the Doctor Who revival in 2005, who stands down next year after filming the three 2009 specials.
The appointment makes Moffat Doctor Who's showrunner, the key creative force behind the programme.Ben Dowell (http://blogs.guardian.co.uk/organgrinder)