LEIGH SALES, PRESENTER: If you thought playing video games was the preserve of mostly teenage boys in their bedrooms, think again. E-sports or competitive online multiplayer video games have become big business. The owners of one of the dominant competitions turned over a billion dollars last year alone and part of that is driven by spectators, not just players. Andy Park met some of Australia's professional gamers as they prepared for a big tournament in Melbourne.

ANDY PARK, REPORTER: It's backstage at Margaret Court Arena in Melbourne. Aaron Bland and his team are about to compete in front of thousands in what is the biggest e-sports tournament yet to be held in Australia.

AARON "CHUCHUZ" BLAND, OCEANIA TEAM GAMER: My parents told they that, like, video games was just, like, a waste of time and this was the main cause of family conflict.

ANDY PARK: The time the 19-year-old plays the game League of Legends almost rivals the amount of time he sleeps or studies.

PENNY BLAND, AARON'S MOTHER: I make sure he goes out with his friends, I make sure that he goes to the gym, I make sure he studies.

AARON "CHUCHUZ" BLAND: When I won the opportunity to go represent Oceania at the Wildcard in Germany, I lied to some of my teachers, saying that I was gonna play professional squash. I guess I was intimidated by the stereotype of what people saw like hardcore gamers.

ANDY PARK: What's the stereotype?

AARON "CHUCHUZ" BLAND: People think gamers are, like, just sweaty nerds who sit inside their Mum's basement and play for, like, 10 hours a day.

ANDY PARK: Sweaty nerds maybe, but the momentum behind e-sports means it's definitely left Mum's basement.

67 million people play League of Legends each month. It's owned by Riot Games, a Californian company who last year turned over $1 billion in revenue. It's one of the biggest games in an ecosystem of emerging professional e-sports competitions.

TAE-HYUNG "RYOO" RYOO, OCEANIA TEAM GAMER: I have never played against these international teams, so I really don't know how I'm gonna fare against them.

ANDY PARK: One of Aaron's Oceania, or OPL, teammates is Korean Australian Tae-Hyung Ryoo.

TAE-HYUNG "RYOO" RYOO: I would put in anywhere between 20 to 40 hours per week playing the game. Gaming in Korea is very big in a sense that there's a lot of involvement at the corporate level.

ANDY PARK: Korean tournaments can have million-dollar prize pools. With sponsors like Samsung and telcos, their teams are run like football franchises, with managers, agents and training camps. Players are now even eligible for US P-1 visas, normally reserved for touring athletes.

E-sports commentators like Jake "Spawn" Tiberi are called shout-casters.

JAKE "SPAWN" TIBERI, SHOUTCASTER: Just like in basketball, everyone has a different position. You have your point guard, which is your, like, All-Star player, you have your big tanky guy, he's your centre. And in the end, the objective of the game is to just take out each other's space.

ANDY PARK: The surprising power behind e-sports isn't the huge numbers of people who play them. It's the huge numbers of people who watch people playing games. Up to 40 per cent of people who watch don't actually play themselves, preferring to clock up something like 16 billion minutes watching others play on platforms such as Twitch, or, they come here, to sold-out cinemas around the country to watch the battle streamed live from Melbourne.

Riot Games, unlike other game tournaments, pays its players a fee for competing regardless of their success. But for all the promise of big jackpots, just covering costs for Australian professional e-sports players can be a challenge.

AARON "CHUCHUZ" BLAND: We earn about $100 each match during the season.

ANDY PARK: And the scandals that have befallen other sports are here too. Some leagues already do random drug testing for performance-enhancing drugs like Adderall and a match-fixing scandal rocked Korean e-sports this year, with 12 StarCraft players arrested.

NEWSREADER: And apparently StarCraft players have been approached by brokers to throw matches for some time.

ANDY PARK: It's all led the Australian e-sports community to informally unionise to help protect players' rights.

CHRIS SMITH, ELECTRONIC GAMING ASSOC. AUST: 'Cause we're talking about money, we're talking about finances, we're talking about people who are often between the ages of 16 to 19 travelling overseas, winning lots of money and at the same time trying to juggle school.

ANDY PARK: Back in Melbourne, Team Oceania is up against Turkey, the team tipped to win, making them the underdogs. Calm exteriors hide the pressure. It's not looking good for the local side.

JAKE "SPAWN" TIBERI: If you make one mistake, you can cost your team your game. It's a game of millimetres in League of Legends and milliseconds, which is how we measure reaction times between players.

ANDY PARK: And suddenly, Oceania's dreams are over. Oceania has come seventh and last.

TAE-HYUNG "RYOO" RYOO: I admit there was a lot of pressure. But I'm definitely disappointed 'cause we lost 'cause I wanted to have the opportunity to go further into the tournament.

AARON "CHUCHUZ" BLAND: We definitely felt we could've done better, honestly. Like, we definitely felt that we didn't do - we could've done better for our region, but at the end of the day, like, we are accepting of what our result was.

ANDY PARK: Aaron's mother Penny has now accepted his gaming.

AARON "CHUCHUZ" BLAND: So my Mum has really come a long way to really start supporting me when it comes to my "e-sports career".

PENNY BLAND: I will help you do the merchandising. That's how I started. I want him to have a girlfriend! I really want him.

AARON "CHUCHUZ" BLAND: Yeah. I'll dream of becoming a millionaire, definitely.

LEIGH SALES: Andy Park with that story.