It was announced today (November 26) that the BBC fantasy drama is to end after its current fifth series, but Murphy confirmed to Digital Spy that plans for a film trilogy are still gathering pace.
"There is definitely ongoing talk and work on a movie, that's true," said Murphy.
The writer/producer added that any potential cinematic version of Merlin would "inevitably" be a reboot of the TV series.
"Will it to some extent be a reboot? Yes, inevitably - any movie would be," he suggested. "[But] will it be with the same or different actors? It's miles too early to tell."
Merlin star Colin Morgan has claimed that the show will "end on its strongest point" when it concludes this Christmas.
"It's come to its highest point - it's grown and grown each year," the Irish actor said in a new video statement. "It has become darker, it has become stronger, characters have grown up, the audience has grown up with it."
Merlin Series 5, Part 1 (episodes 1-6) is released on DVD on November 26, 2012. Series 5, Part 2 and the Complete Series 5 DVD/Blu-Ray are released on January 21, 2013 on Fremantle Media Enterprises. Order on www.amazon.co.uk.
> Poll: Is it the right time for Merlin to end?
> Merlin final series: Colin Morgan, Anthony Head on show end
Watch the stars of Merlin discuss the movie trilogy with DS below: