The Algerian striker and Al Hasawi announced on Saturday night via Twitter that a medical had been passed, but the transfer is yet to be fully announced by the club.
Al Hasawi also suggested that there would be further business for promotion-chasing Championship club Forest before the transfer window closes on Friday night.
"I am close to finishing Rafik Djebbour's transfer and will do all I can to strengthen further this month. #nffc," he tweeted.
Djebbour, 29, was set to join Forest last summer but the deal fell through and he has since been on loan with Turkish club Sivasspor, scoring twice in 10 league appearances this season.
Last term he netted 20 goals in 25 league games for his parent club Olympiacos.