The unattached ex-Leeds United and Liverpool winger was named by Verbeek as captain ahead of his side's March meeting with Singapore, and the Dutchman insists that Kewell is 100% better' than he was two months ago.
Kewell's international career has been continually interrupted through injury, and as a result, he has appeared only 32 times for his country in more than a decade.
However, Verbeek is confident that Kewell is both mentally and physically fit before Sunday's important World Cup qualifier against Iraq on Sunday.
He said: "Harry's a fantastic player. The Harry Kewell I've seen in these two weeks is 100 percent better than the one in Singapore. At that time, he was struggling a little bit both mentally and physically.
He's fit and ready, he's very good in the group. He's trained every training session from the first to the last minute. He wants to show what he can do."
He went on to hail the player's special attributes: "He's as important as all the other players, but he has special qualities. He has to use his special qualities and the rest of the team has to make sure he can use his special qualities.
"If they have everything, they will all play to the best of their ability. Harry has special qualities and my job is to create a team where we all can use our special qualities and hide our weaknesses."
Of his decision to award Kewell the Australian captaincy, the Dutchman paid tribute to the experience of his European-based players.
He also declared himself happy with the progress the player is making with the responsibility of skippering the side: "It's a big responsibility. I'm a lucky man, I have a lot of experienced players available to lead this team, Vince Grella, Brett Emerton, Mark Schwarzer.
"Harry is doing very well. And I'm not the sort of person to change things around, Harry's the captain tomorrow."