Lawyers for Stallone, the 60-year-old star of the "Rocky" and "Rambo" movie franchises, represented him in a Sydney court on Tuesday where he faces one charge of importing a banned substance.
Prosecution documents handed to the court said Stallone had marked "No" on a customs declaration card that asked if he was bringing into Australia restricted or prohibited goods "such as medicines, steroids, firearms, weapons, or any kind of illicit drugs."
• Read about more highbrow hijinx in the Celebrities in Trouble Center.
But an X-ray of bags among his entourage on their arrival Feb. 16 to promote Stallone's latest "Rocky Balboa" movie prompted a search that revealed 48 vials of the human growth hormone product Jintropin, made by Chinese firm GeneSciene Pharmaceuticals, the court heard.
Stallone and his team were held at Sydney airport for several hours after arriving on a scheduled Qantas Airways flight. His hotel room and the private jet he planned to fly out on were searched three days later, when he was handed a summons by customs officials to face court.
"You have not been validly prescribed the goods by a medical practitioner for any medical condition suffered by you and for which the goods are recognized medical treatment," Stallone was told in a customs document handed to the court Tuesday.
Stallone did not appear in the Sydney Local Court for Tuesday's hearing, and was excused from appearing at another hearing scheduled for April 24 as long as a lawyer appears on his behalf. He will be required to enter a plea at the next hearing.
Human growth hormone, a naturally occurring substance that can be replicated synthetically and is used to build muscle mass, is considered a performance enhancing drug in Australia and it cannot be imported without a permit from the Therapeutic Goods Administration.
The maximum penalty for bringing it into Australia illegally is a fine of $86,000 and five years in prison, but court can only impose a fine of $17,000.
During his visit to Australia, Stallone shrugged off the airport incident.
"It was just a minor misunderstanding," Stallone told reporters "They were just doing their jobs. I just didn't understand some of the rules here."
Get full coverage in FOXNews.com's Celebrities in Trouble Center.