Bale impressed with two goals in a match-winning performance in Wales' World Cup qualifier against Scotland last week, earning Chris Coleman his first win in charge of the national side.
"He's an amazing, amazing talent and he's after the Ronaldos and Messis of this world and he's getting better and better," Redknapp told BBC Sport ahead of Wales' qualifier against Croatia. "He's almost unplayable when he's on his game. He is a genuine world-class player."
He added: "There's nobody he couldn't play for. He'd improve any team. He is already at the top but any team in the world would love to have Gareth Bale playing for them."
Bale, who was named Professional Footballers' Association Players' Player of the Year in 2010-11, is contracted to Spurs until 2015.
Redknapp managed Bale during his four years at Tottenham and thinks the 23-year-old has developed into a real game-changer since he shot to international fame with his first hat-trick in Spurs' Champions League defeat by Inter Milan two years ago.
"He can do everything and could play anywhere. He's the full package," Redknapp said. "He can head it, he can dribble, he can shoot, he's got a great physique. He's an amazing athlete, he can score with both feet - there are no weaknesses in his game.
"It was amazing how he turned the game around [against Scotland].
"With 10 minutes to go you're looking for somebody who can do something special and Gareth can do something special.
"He is a great lad as well with a good family behind him. It couldn't happen to a nicer lad."
Source: PA
Source: PA