One of the states elite sporting schools has acknowledged a third student was involved in a steroids scandal that has rocked the institution.

Two students at St Joseph's Nudgee College, aged 16 and 17, were arrested on Tuesday on charges of possession and supply of steroids. Both were expelled.

But in a statement this afternoon, College Principal Daryl Hanly said a third student was "cautioned."

Mr Hanly said the arrests were not linked to the school’s highly-touted athletic program, but highlighted "issues associated with body image for young men."

Read the full statement from Nudgee College HERE: St Joseph's Nudgee College Media Statement

-- by Tuck Thompson, Brittany Vonow, David Murray

Overnight, the investigation into a steroid scandal at one of the state's top sporting private schools was expected to expand, with mobile phones seized and classmates interviewed.

A student was found to have the illegal drugs at St Joseph's Nudgee College, with police confirming two males, aged 16 and 17, were arrested on Tuesday on charges of possession and supply of steroids.

Muscle-building steroids can cause a range of dangerous health and mental side-effects. They are also performance-enhancing drugs, leading to charges of cheating when athletes are caught using them.

The 16-year-old was arrested under the provisions of the Youth Justice Act. The 17-year-old, from Clayfield, was charged with four counts of supply of a dangerous drug and two charges of possessing a dangerous drug.

He will be dealt with under the drug diversion program.

The school's principal Daryl Hanly emailed parents and guardians yesterday after being contacted by The Courier-Mail.

"In response to information provided to us, a student was found with illegal substances on campus, believed to be steroids," Mr Hanly wrote.

"Due to the serious nature of this issue, police were immediately contacted and continue their investigations."

The college was also conducting its own investigation of the "serious incident," he said.

Mr Hanly assured parents the safety of their sons was the college's "highest priority."

"The use of any illegal or inappropriate substance will not be tolerated at Nudgee College."

Mr Hanly declined to be interviewed yesterday.

He would not confirm the 17-year-old's connection to the college, or what disciplinary action had been taken against the young men.

It is understood the student or students have been expelled.

The arrests occurred at a time when Nudgee's First XV rugby players were playing in the Sanix World Rugby Youth Tournament in Japan.

Nudgee was selected by the Australian Rugby Union as this year's high school to take on some of the best high school teams in the world

In the letter, Mr Hanly urged parents not to speak to the media.

Originally published as Third student involved in steroids scandal