Matosevic, 40, reached a career-high singles ranking of 39 in 2013. He retired from the sport in 2018 and has since become a coach, working with Australian players Chris O'Connell and Jordan Thompson.
"An independent tribunal determined that Matosevic committed five anti-doping rule violations between 2018 and 2020...," the ITIA said in a statement.
"... including use of a prohibited method through blood doping (while an active player) and facilitating another player to blood dope, providing advice to other players on how to avoid positive tests, and use and possession of the prohibited substance clenbuterol."
In a statement published by Australian tennis website 'The First Serve' in February, Matosevic admitted he underwent a blood transfusion in Morelos, Mexico towards the end of his playing career.
"I was disgusted with myself, I retired the following week at the age of 32-and-a-half," he added.
"Shortly after I realised how precious life is and how serious and reckless my decision was. I wasn't involved in tennis at all for almost two years and pro tennis for three.
"I am writing this confession letter firstly to warn other athletes against doing anything that may harm their health and put their lives at risk because there is a long life after an athlete's career."
In the same statement, Matosevic slammed the ITIA's methods, alleging that many of the claims against him were based on his text messages and saying that the anti-doping systems in tennis needed to be "dismantled".
"The tribunal also dismissed Matosevic's public allegations relating to the integrity of the ITIA's investigation process as without merit, and that the ITIA 'acted within the authority conferred by the (Tennis Anti-Doping Programme)'," the ITIA said on Monday.