"OMG the whole club just got shot up!!!" he wrote on Facebook, according to Perth Now.
"We all had to get on floor and wait. The gunman ran around then everyone legged it. I filmed the whole thing. We all OK."
Tim Mullen, from Perth, told 9 News he was with friends at the festival when he heard gunshots.
"As we sat down there was more and more screams running through the club," Mullen said.
"You could hear the gun shots getting close and then they were, like, directly behind us maybe within five metres. I know that I ran past four victims and there was at least two others behind me that I didn't see, where or not they are all dead or not, I'm not sure."
Australian DJ Wax Motif claimed in a series of tweets he had seen the horrific shooting unfold.
"Guy 5m in front of us got shot. We all jumped the fence to get out and saw at least 4 bodies down on the escape. #BlueParrot," he said in one tweet.
"We ran down the beach cos we saw bodies in the alleyway next to club then another gunman started charging down on us from up the beach," he wrote in another.
Video taken at the club purportedly show dozens of people fleeing the scene in panic. In one, shouts of "he's got a gun" can be heard.
Scottish DJ Jackmaster issued a warning to clubbers after shots rang out, tweeting "Stay in ur f****n hotel."
A second shooting was then reported at a closing party at The Jungle - another club taking part in the event which attracts DJs from across the world. These reports have not been confirmed.
Valerie Lee, Mixmag's US Digital Editor, was at the Elrow closing party at The Blue Parrot when the shots rang out.
"We were in the backstage area, which is super close to the main entrance. At least four to five shots were fired," she told Mixmag.
"People started running because there's an exit in the back. We stopped and hid behind a cement wall, then crawled under a metal table.
"Security guards at first didn't think it was shots and kept claiming it was fireworks, saying everything was OK. Then people kept running and said they saw a gun. We kept hiding until they opened the back gate and we ran outside."
Local TV station EMAC TV reported that the mass shooting is believed to be related to a drug gang turf war or cartel-related.
Festival organisers issued a statement on Facebook: "The BPM Festival has been working closely with the local authorities (Seguridad Publica / Policia Turistica) throughout the festival to ensure public safety and security for all visitors.
"We are overcome with grief over this senseless act of violence and we are co-operating fully with local law enforcement and government officials as they continue their investigation."
OFFICIAL STATEMENT (UPDATED*):
It is with great sadness to share that police have confirmed reports of a lone shooter...
Posted by The BPM Festival on Monday, 16 January 2017
The BPM festival is an annual event running from January 6 to 15 this year, its 10th anniversary.
Along with thousands of people, the event featured more than 375 artists.
Playa del Carmen is 68 kilometres south of Cancun. The region, popular among American and European tourists, has been largely spared from the drug violence plaguing other parts of Mexico.
The shooting represents a blow to the country's tourism industry, which has been one of the few bright spots in the economy thanks to a weak peso exchange rate.
