Iniesta finished behind Messi and Ronaldo last year for the award, while he came second to Messi in 2010 after helping Spain win the World Cup.
"Iniesta would definitely deserve a Ballon d'Or," Deco, who retired in August, was quoted as saying by El Mundo Deportivo.
"What's happening is that all the attention in the media goes to Messi due to his great performances. However, the players all realise that Iniesta is absolutely amazing.
"If I had to compare him to someone, I would say Zinedine Zidane. Andres is phenomenal.
"The problem is that he has two animals ahead of him in Messi and Cristiano Ronaldo. Because there's no denying that Cristiano is a beast as well," concluded the ex-Portugal international.
The 23-man shortlist for Fifa's top individual prize will be announced on October 29.