AUSTRALIA'S highest-paid athlete has slammed claims that he was denied entry to Melbourne's Crown Casino last night for breaching the gaming venue's dress code.

NBA basketballer Ben Simmons, 23, told his 4.3 million Instagram followers he was asked for ID when he tried to enter the gaming floor at the casino with three of his friends before allegedly being turned away.

In a now-deleted video Simmons posted on Instagram, the Philadelphia 76er suggested he and his friends were turned away because of their skin colour, while one friend, Alex Subers, wasn't checked, also because of his skin colour.

"I find it so crazy that the only guy who doesn't get checked to go into the casino is this guy," the Philadelphia 76ers star said in the video.

"I get checked, Mike gets checked and Tys gets checked.

"Thank you Crown Casino, damn, and they didn't let me in, or him or this guy. Wow, we got a long way to go."

After suggestions on social media that he was in breach of Crown's dress code, which includes a ban on "camouflage clothing" and "active sporting attire".

Simmons was clad in trendy Nike camouflage-print trackpants, but revealed that Subers - who was allowed entry - also wore a similar outfit.

Social media users have slammed the Melbourne casino, claiming "racist bouncers" were to blame for the incident.

The video was shot near Crown's food court, where Simmons stopped for a photo with a fan.

A source said the group was swearing and refused to show ID before they were declined entry.

But Simmons has also denied claims that they refused to hand over identification when asked.

In a statement, Crown Casino said it "strenuously rejects" reports that it discriminated against a group of visitors last night.

"Crown's internal security policy requires our security officers to check identification of those persons they believe to be under the age of 25," the statement said.

"This is an enhanced safeguard to ensure that no one under the age of 18 is permitted entry to the casino floor as required by law.

"The group subsequently provided identification and were permitted entry. Crown is an inclusive workplace."

The incident has spread to the US and made headlines, with Sports Illustrated, TMZ and other news outlets reporting he was denied entry due to racial profiling.

It comes after the NBA superstar last week walked the red carpet in support of AFL legend Adam Goodes, at the premiere of The Australian Dream documentary.

Simmons is an executive producer for the film, and plans to take it to American audiences.

He was also spotted in a corporate box with model Talia Richman at the weekend's Essendon AFL game.

The 2018 Rookie of the Year recently signed a contract extension worth $US170 million ($A242 million) to stay at Philadelphia, the richest sporting contract ever signed by an Australian athlete.

But Simmons left fans dismayed when he pulled out of Australia's exhibition matches against the USA and Canada, after indicating he was available to play in Perth and Melbourne this month.

"I want to thank Basketball Australia for their continued support and I'm committed and excited to compete in the 2020 Olympics in Tokyo," he said at the time.

Crown was forced to launch an advertising blitz to downplay claims of money laundering and organised crime links which engulfed the casino last month.

The federal government ordered a powerful inquiry after the casino was engulfed in a storm over its use of junket operators to bring Chinese high-rollers to Australia, with reports of money laundering, fast-tracked visas and sex trafficking.

Crown has been contacted for comment.