Mel Gibson May Sue Over Rant Tape Release

Sources connected with Mel tell TMZ ... the actor believes he has a "basic human right" NOT to be secretly recorded in his own home.

We're told Mel's people are looking at the laws of Costa Rica to determine if recording laws were violated and, even if they weren't, if Mel's right of privacy was violated by the release of the audio.

Mel explodes in the recording about Eszterhas' lack of progress with "The Maccabees" script -- "What the f**k have you been doing!!" He also unloads on Oksana Grigorieva, calling her a ""F**king c**t, c**ksucking whore."

We're told Mel believes anyone recorded "at their worst moment" would sound awful, and it's unfair to trap people in their refuge.