"The Croatian authorities have to understand the importance of the problem of violence and hooliganism," Platini said in an interview with the influential Jutarnji List daily.
"However, unfortunately, we are still awaiting for an adequate reaction. My advice is not to wait for too long since the consequences could be fatal for Croatian football," the former France captain was quoted as saying.
Platini was expected in Zagreb later on Tuesday, where he was due to attend ceremonies marking the 100th anniversary of the Croatian Football Federation (HNS).
FIFA president Sepp Blatter was also expected for the celebrations.
Platini said he believed the HNS's new leadership, elected earlier this year and headed by former star player Davor Suker, would 'eventually resolve the problem of violence'.
"To do that, brave people and brave decision are needed but also strong political support," he emphasised.
Platini has previously warned Croatia, as well as neighbouring Serbia, that if they do not root out violence among football supporters they risk being excluded from international competitions.
UEFA has fined the HNS on several occasions for violence and racist behaviour of Croatian hardcore football fans who often clash with the police.
At EURO 2012, UEFA fined the HNS 80,000 euros ($100,044) after its supporters racially abused Italy's Mario Balotelli in a group match in Poznan, western Poland.
A racism monitoring body said that up to 500 fans were involved in racist chanting, while an AFP photographer positioned in front of the majority of Croatia supporters said he heard taunts and saw a steward pick up a banana from the pitch.
A Croatian court on Monday sentenced eight hooligans to prison terms of up to two-and-a-half years for attacking a bus of PAOK fans ahead of the Greek club's UEFA Europa League match two years ago.
Four Greek fans were injured in the violent incident in December 2010 in the Croatian capital ahead of PAOK's match against Dinamo Zagreb.
