Damon was discussing his role playing Liberace's lover, Scott Thorson, in the HBO film Behind the Candelabra, when he made the comments.
Using his friend Rupert Everett as an example, Damon said he thought being openly gay might hinder an actor's career.
"I don't want to, like [imply] it's some sort of disease - then it's like I'm throwing my friends under the bus. But at the time, I remember thinking and saying, Rupert Everett was openly gay and this guy - more handsome than anybody, a classically trained actor - it's tough to make the argument that he didn't take a hit for being out," Damon said.
Everett was once considered a front runner to play James Bond before the role was handed to Daniel Craig.
Duncan Matthews, general manager of Rainbow Youth said "if Matt Damons is saying that, it means there's a lot of work to do in order to make people feel safe about coming out."
OUTLineNZ general manager, Trevor Easton, said "I can completely understand where he is coming from, which is very sad. When celebrities do come out, however, it does a lot to support people in their coming out process."
- nzherald.co.nz