Okkas, 29, is out of contract with Greek giants Olympiakos at the end of the season and is hoping to secure a move to the Premiership.
That may come as soon as the January transfer window if Hughes likes what he sees and Rovers can come to an agreement with the player's Athens employers.
Okkas, who has won over 60 caps for his country, said: "The interest and the invitation of Blackburn is a great honour for me.
"They are one of the best English clubs with a great history. Many big players have played for this club in the past.
"I hope everything is going to be OK and I can become a Rovers player. Of course, everything depends on my current club, Olympiakos. I will go next month to England for the trial. If the two clubs agree terms, then I will play for Rovers.
"To play in the Premier League is a big dream and a great honour for me. This is the best league in the world at the moment and every player wants to have the chance to play there," he added to Sky Sports.