The 'Fancy' rapper says 17-year-old Lorde shouldn't have appeared with the late singer's former Nirvana bandmates at the Rock 'n' Roll Hall of Fame induction ceremony earlier this year, as she is too young.
She told Billboard.com: ''Nothing against her, but I think when you're doing a tribute to someone that's dead, generally it should be the person's peer.
''Lorde is not Kurt Cobain's peer. No matter if she killed the performance or not, I just don't think it's appropriate.''
Lorde closed the segment, singing Nirvana's track 'All Apologies'.
Although Iggy may not think she was right for the show, Kurt's former bandmate, drummer Dave Grohl, was impressed with her performance.
He claimed Lorde ''resembled and represented the Nirvana aesthetic'' adding: ''She has an incredible future ahead of her as a writer, performer and vocalist.''
Kurt took his own life in 1994, aged 27.
Take a look back at October's inaugural event.
The film is expected to continue without Mendes' involvement.
The sins of London have followed them home. After throwing Owen Shaw (Luke Evans) out...
The cast of 'Furious 7' talk about their favourite moments from the 'Fast & Furious'...