The Manchester City striker's signing was not ratified ahead of yesterday's 5pm transfer deadline, but Sunderland officials claimed they had been unable to submit the necessary paperwork because of technical problems.
The Premier League have examined Sunderland's claims, and confirmation of Benjani's loan move was confirmed this afternoon.
Benjani will provide competition to the Black Cats' current first-choice strike pairing of Kenwyne Jones and Darren Bent.
Sunderland boss Steve Bruce said: "He's a big, strong powerful centre-forward and one we've been tracking for a long time.
"I'm delighted that we've been able to bring him to the club. He'll bring another dimension to our striking options and will be a great addition to the squad."
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