The Aussie rapper -- who birthed her and Carti's son, Onyx, in 2020 -- hopped on the 'Dinner's On Me' podcast this week and was asked point blank about her family dynamic ... and Iggy made no bones about the fact she believes she's on her own in parenting.

Iggy says, "I'm very much a single mother. I'm very much the only parent, no disrespect, but yes, I am not co-parenting really, and that's just the reality of it. It's one, it's 24/7."

She went on to reflect on motherhood and how her son has taught her to be present and to prioritize family time over other trivial matters -- and, IA even attributed a lot of her success to her son as well, saying he's her biggest fan. But yeah ... she's definitely crapping on Carti.

FWIW ... Iggy has accused Carti of being an absent father in the past -- making it very clear that she doesn't see him as a shining example of parenthood ... it's been a years-long saga.

While Carti has been mostly quiet about Iggy's claims -- he's pretty private in general -- Iggy often posts pics of their kid on social media ... and she certainly looks very involved.