The 33-year old Australian international is currently available on a free transfer after leaving Melbourne Victory in June but has so far been unable to find a new club with the likes of Stoke City, Blackburn Rovers, Middlesbrough and Swindon Town all linked at some point.
According to Benitez, who managed Kewell at Anfield after he arrived from Leeds United in 2003, feels that the Socceroos star can still mix in England's top flight and has urged clubs to go after his signature.
"He still has the level for a Premier League club," Benitez told au.fourfourtwo.com.
"He's a player that is good in the air, can keep the ball, can beat players and can score goals.
"It's just a question of finding the right club for him.
"He was someone that could make the difference, but was just unlucky with injuries especially in finals, but as player I really liked him," added Benitez.
"His injuries were a pity as I believed he could have made a difference in a lot of games."