The actor, who played King Leonidas in the 2007 action movie, said that he would reprise his role in the planned sequel if the screenplay was well-written.
"If the script was good, I would do it," Butler told People. "I've got to feel that there's a real reason to go there, to do a second one, because I loved the first."
The 41-year-old went on to say that he has high hopes for the sequel.
"I hope that they write a great script and I hope that I love it," Butler said. "That was my favourite role, and it would be great to go back there and have some fun with it."
The sequel's producer Bernie Goldmann recently revealed that roles for both Butler's King Leonidas and Lena Headey's Queen Gorgo have been written into the film.
In August, Butler signed on to star in The Bricklayer, playing a maverick FBI agent.
Titled 300: Battle of Artemisia, the highly-anticipated sequel is slated for a 2013 release.