Former world snooker champion Neil Robertson has backed Ronnie O'Sullivan's assertion that the sport is no longer a desirable career, saying that the expanded tour makes it unaffordable for all but the top players.

Five-time world champion O'Sullivan, who has estimated career earnings of £8.6m - making him the second highest earner of all time behind Stephen Hendry - told RTÉ 2fm's Game On in an exclusive interview on Wednesday that he would advise those considering a professional career to try another sport instead.

"Don't do it," O'Sullivan said. "That's the advice I give to my son.

"I would say: 'put your gear away, go and take golf up, take tennis up. Stay away from this game.'

"It's a very solitary sport. A very technical/mental sport. It's a lot of hard work for maybe not massive rewards compared to motor-racing, tennis, golf, athletics."

World no 7 Robertson, with career earnings of £3.2m, today weighed in behind 'The Rocket', tweeting: "I wouldn't recommend this sport as a "career" while there is 128 on the tour either. Atm [at the momet] it's top 20 or you're better off flipping burgers.

The Australian later added: "Not discouraging. Just make sure you get an education 1st or during. Unless you get top 20, you won't earn enough to cover the bills.

"I disagree with how Ronnie is making it sound. I would just like to see a better structure to support the majority on it."

Since world snooker chairman Barry Hearn took stewardship of the game in 2010, the snooker tour has expanded the number of ranking events to 20 and doubled the number of professional tour cards to 128.

The cost of travelling to the growing number of tournaments in China and increased number of players vying for prize-money has attracted criticism from O'Sullivan and others, who feel the the quality of competition has been diluted.

Speaking in November, O'Sullivan said: "China is where it is at. The money is there, they are ready to pump it in to snooker, they just don't want 128 players.

"It is anarchy when you go over there (to compete in a 128-player tournament), you watch it and it is just too many players, too many people. They want the cream of the cream - and that is the top 32."

"I think we have a lot of quantity, but very few quality events, so maybe skim them down a bit and just make them all real proper set-ups.

"Maybe the tour is only strong enough at the moment to cater for 64 players to do that.