The 27-year-old has been included in Joachim Löw’s 23-man squad which will travel to France.
“Ozil has been growing at Arsenal but the problem with him was always consistency,” Hamann was quoted as saying by the Daily Star.
“You wouldn’t say he only did it in flashes because it might have been six weeks where he was doing well, but this season he’s been doing it for three, four or five months in a row.
“He’s maybe a bit underrated for the German side, even though he has always had a big role to play.”
Ozil won the World Cup with Germany in Brazil back in 2014. The 27-year-old has had a terrific season at Arsenal providing the highest number of assists in the Premier League (19).
The Germany international was also voted Player of the Season for his efforts but his club were unable to lift a trophy. The European Championships remain the only trophy Ozil will be able to lift this season.