SYDNEY: Hollywood star Sylvester Stallone has pleaded guilty to bringing vials of human growth hormone into Australia.

Sydney's Downing Centre Local Court has been told Stallone admitted two charges of importing a prohibited import when he arrived at Sydney airport from the US in February.

The Australian Customs Service alleged Stallone, 60, imported 48 vials of human growth hormone in five boxes when he came to Australia to promote his latest film Rocky Balboa.

The star of the Rocky and Rambo films was due to enter a plea last month, but the court heard that "medical material" sent by Stallone to Australia needed to be analysed by Customs first.

Customs alleged that officers found the boxes of human growth hormone when Stallone alighted from Qantas flight QF8 from the United States on February 16.

Documents previously tendered to the court alleged Stallone ticked the "no" box when asked to declare whether he was bringing in restricted or prohibited goods, "such as medicines, steroids, firearms or any kind of illicit drugs".

The documents alleged the active ingredient in the substance, going under the brand name Jintropin, was the human growth hormone somatropin.

The court documents revealed that the court attendance notice was issued on February 19, the same day that Customs officials raided his room at the Park Hyatt hotel.

When questioned by reporters, Stallone would not identify the substance but said "it's something that I've taken for years", and "it's not dangerous".

The maximum fine for the offence is $A110,000, but Stallone faces a maximum penalty of $A22,000 because the charge is being dealt with in a local court.