The pair, who split in 2010, after a one-year relationship, have had a long-running and acrimonious settlement dispute, rife with reports of alleged domestic abuse.
The Russian singer has previously claimed she suffered the abuse during the time she was in the relationship with the actor.
In the expletive-laden tape, which was recorded in 2010, and recently obtained by Radar Online, a ranting Mel Gibson can be heard harassing Grigorieva about having fake breasts, and for breastfeeding their baby daughter, Lucia, with implants in place.
Gibson can be heard saying, “You’re trying to breastfeed with f------ foreign bodies in you.”
Grigorieva responds, “That has nothing to do with it.”
Gibson then goes on to accuse Grigorieva of lying to him about having fake breasts, which Grigorieva denies.
Incensed by Grigorieva’s reponse that her breasts “aren’t his f------ business”, Gibson unleashes a tirade of misogynistic and racist abuse.
Contains offensive language
"It is, it is. They look stupid. I'm just telling you, just an appraisal ... keep 'em if you want. Look stupid, see if I give a f--- . You know, but they're too big and they look stupid. They look like some Vegas b----, they look like a Vegas w---- and you go around sashaying in your tight clothes and stuff. I won't stand for that anymore," Gibson says.
Grigorieva tells Gibson she never wears tight clothes, and rarely leaves the house, a response that sends the already enraged Gibson, into an apoplectic fit.
"You go out in public and it's a f------ embarrassment to me! You look like a f------- b---- on (ecstasy). And if you get raped by a pack of n------ it'll be your fault. All right? Because you provoked it. You are provocatively dressed all the time, with your fake boobs you feel you have to show off in tight outfits and tight pants,that let me see your p---- from behind".
The leaked audio comes a day after the Californian Court of Appeal ruled Gibson no longer had to pay his ex the remaining $500,000 ($653,000) in child support.
A settlement agreement had been struck by the pair, which prevented Grigorieva from publically speaking about the alleged domestic abuse claims.
TMZ reports Grigorieva breached these conditions, when she spoke to Howard Stern about the relationship in an interview she gave to Stern on his show 2013.