The 17-year-old has agreed a deal to join the Blaugrana from Dinamo Zagreb in the close season, with his solicitor insistent the move will still go ahead despite the transfer ban imposed on Barca by FIFA.
Suker, who is now president of the Croatian Football Federation, says that the Spanish champion's supporters can put their faith in his young compatriot.
"Halilovic is a star," he is quoted as saying by Cope. "He reminds me of Messi. He is young, but we can trust him and he handles the ball very well."
Barca has been struggling of late, but Suker believes that the team's recent struggles are just part of football.
"Life is like the moon - up one day and down the next. Hopefully we can enjoy Messi, Xavi and Andres Iniesta... In football you can't always be on top."
Suker, who represented Real Madrid as a player, is backing Atletico Madrid to claim the Liga title this season due to its superior fighting spirit as the title race goes down to the wire.
"No one was talking about Atletico Madrid at the start of the season and I'm very happy for them and their fans, who are an example," he added. "Atletico have the biggest chance to win La Liga because they are more hungry."