Ben Simmons says he was offered gifts including Rolls-Royce and Bentley cars, watches, jewellery and a house while forced to play one season as an “amateur” at Louisiana State University.

The 20-year-old Australian basketball prodigy has given sensational insight into his rocky LSU stint and slammed the body that regulates US college sports, the National Collegiate Athletic Association, for the double standards he says it forces on young athletes.

Simmons’ revelations are exposed in a new documentary One and Done scheduled to air on US TV network Showtime on Friday (Saturday AEDT).

“Bentley, a Wraith Rolls-Royce, watches, jewellery, a house ... anything,” Simmons, rattling off the gifts he was offered while at LSU, says in the film according to ESPN. “It literally is anything. People coming at you, offering you things.”

A new Rolls-Royce Wraith sells for around $US300,000 ($A391,000) in the US. Simmons declined the offers and does not say who offered him the gifts.

Melbourne-born Simmons was the hottest young basketball talent on the globe last year when as a 19-year-old he was required under NCAA rules to play at least one year at college before becoming eligible to enter the NBA.

Sports agents and shoe companies hovered around him in the hope of signing him. On a trip to a sports shoe store Simmons says the salesman would “let me take whatever” if he asked.

The documentary follows Simmons from his time as a prodigy in Australia, his move to Florida’s Montverde Academy for his high school years, his season at LSU and then the Philadelphia 76ers selecting him No1 this year at the NBA Draft.

It also shows the behind-the-scenes tension between Simmons, his parents Dave and Julie and sister Emily Bush as Bush begins to manage his career.

Simmons was criticised during his LSU stint for not attending classes or maintaining high enough grades to qualify for the elite Wooden Award for best college player.

The documentary shows how apathetic Simmons was toward his studies, how he believes the NCAA makes huge sums of money off amateur athletes and how he could “be a voice for everybody in college”.

“The NCAA is messed up,” Simmons says. “... Don’t say I’m an amateur and make me take pictures and sign stuff and go make hundreds of thousands of millions of dollars off one person. I can’t get a degree in two semesters, so it’s kind of pointless.”

His mother appears to support his view. “If you get a kid who’s a child prodigy and plays the violin amazingly, no one’s saying to them you must go to college for a year before you join the philharmonic orchestra,” Julie Simmons says in the film.