Saadi, who has had spells in Italy as a player with Perugia and Udinese, currently owns 7.5 percent of the Turin giants through his Libyan Arab Foreign Investment Company.
"It is our intention to make a big investment," Al-Saadi told Italian newspapers.
"We would like to be the biggest shareholders after the Agnelli family. Naturally, they remain the historic pillar of Juventus. We are looking at being the Agnellis' main partner.
"At the moment we haven't gone into detail, but it is our firm intention to raise our quota in the club. I still don't know when we will have something concrete."
The player who has been politely described as having modest talent also claimed he is considering an offer to train with Serie A club Sampdoria.
"I will speak to my father about it before making a decision," he said.
"I have to see if it would get in the way of my work commitments. But I like the offer made by (Sampdoria president) Riccardo Garrone."
Juventus were relegated to Italy's second division and made to start on minus 17 points for their part in the country's match-fixing scandal.