The Australian Olympic Committee (AOC) says it will further investigate allegations of drug use and bullying during the London Olympic campaign after the 4x100m swimming team admitted to using Stilnox.

James Magnussen and his relay team-mates have admitted to behaving inappropriately at a pre-Olympic bonding session last year.

Magnussen, Eamon Sullivan, James Roberts, Matt Targett, Tommaso D'Orsogna and Cameron McEvoy fronted a media conference in Sydney this afternoon.

In a statement they outlined their use of Stilnox during a bonding session while in camp in Manchester prior to the London Games, where the 4x100 metres freestyle relay squad finished fourth.

Stilnox was banned by the Australian Olympic Commitee about three weeks before the London Games, but it is not considered a performance enhancer.

The AOC now says it will consider withdrawing funding from five of the swimmers - Magnussen, Sullivan, Targett, D'Orsogna, and McEvoy.

Roberts is the only member of the team who says he did not use Stilnox.

The drug was prescribed to both Sullivan and Targett prior to their arrival in the Manchester camp and before the ban. They say their scripts were filled in Australia.

What is Stilnox? Prescription drug used to treat insomnia and some brain disorders

Prescription drug used to treat insomnia and some brain disorders Sometime prescribed to athletes who are having trouble sleeping before big events

Sometime prescribed to athletes who are having trouble sleeping before big events Prescribing it to Australian Olympians was banned just before the London Games

Prescribing it to Australian Olympians was banned just before the London Games But the relay team say their prescriptions were issued before the ban was announced

But the relay team say their prescriptions were issued before the ban was announced Recreational users take Stilnox and deliberately resist its sleep-inducing effects

Recreational users take Stilnox and deliberately resist its sleep-inducing effects Doing so can induce a feeling of a 'high' as well as visual effects

Doing so can induce a feeling of a 'high' as well as visual effects Its recreational use has been reported by other elite sportspeople including cyclists

All six members of the freestyle relay squad will face a newly formed integrity panel put together by Swimming Australia (SA).

The relay squad admitted to taking part in a bonding session that involved using Stilnox after attending a movie and dinner.

In a statement the team said it was seen as a way of continuing a "recent tradition on the men's team".

The swimmers also admitted to making prank calls to other team members, while also knocking on room doors.

They claim they were in bed by 10:30pm and admit their behaviour was "childish and stupid".

'Ridiculous choice'

Sorry, this video has expired Swimmers own up to Stilnox use

Magnussen, who finished second after entering the Games as the overwhelming favourite to win the 100m freestyle gold, says he deeply regrets his role in the bonding session.

"I think one of the reasons that I agreed to go along with this night was I was feeling under so much pressure and it had been building for the best part of a year," he said.

"The chance to sort of bond with these guys and be normal for one night were my intentions of the night.

"Obviously in hindsight a ridiculous choice and a ridiculous method to do that by and for that I have a lot of regrets.

"But I don't feel it affected my performance."

Eamon Sullivan denies that he and Matt Targett were confronted by Leisel Jones because they were bullying a young swimmer at the time by calling him fat and slapping him around the head.

Space to play or pause, M to mute, left and right arrows to seek, up and down arrows for volume. Listen Duration: 5 minutes 43 seconds 5 m Elite swimmers admit drug abuse ( Martin Cuddihy ) Download 2.6 MB

"Not at all. That's a completely false statement," Sullivan said.

He says the Stilnox use was purely a matter of bonding, which continued on a tradition within the Australian team.

"Hindsight is a wonderful thing," he said.

"Of course I regret our decisions and my decision. And as a senior member of the team I should've stood up and shown more leadership at the time. For that I'm truly sorry.

"If I thought for one moment that these actions and our communal decision to take Stilnox would affect our performance in no way I would've done it.

"Stilnox is out of your system in seven hours. It's something I have used for years for racing.

"Being able to get to sleep instead of staying awake at four in the morning and getting up at six for racing."

'Vital step'

The admission from the team follows this week's release of two independent reviews that alleged swimmers abused prescription drugs and alcohol prior to the Olympics.

The reviews reported a litany of failings by the sport's leadership and revealed a "toxic culture" within the Olympic team which contributed to a disappointing performance.

SA chief executive Barclay Nettlefold says his organisation has spoken with a female member of the squad, who was woken by the relay squad.

Space to play or pause, M to mute, left and right arrows to seek, up and down arrows for volume. Listen Duration: 5 minutes 28 seconds 5 m Olympian Dr Peter Larkins says private use of Stilnox staggering Download 2.5 MB

"Swimming Australia has been in contact this day with the person who was interrupted by the bonding session and she has informed us she did not feel threatened by such actions but was disappointed she was woken up," he said.

"She also expressed disappointment in the way she was represented in a paper article today."

Nettlefold also said he is standing behind under-fire coach Leigh Nugent, after reports emerged he turned a blind eye to the bad behaviour.

"I've come out openly and stated that Leigh Nugent is the head coach of Swimming Australia. And I continue to say that to this day," he said.

Nettlefold says he hopes the episode will be bring forward a fresh chapter for the sport in Australia.

"On behalf of Swimming Australia I would like to commend the boys on coming forward to us and explaining their story openly," he said.

"We see this as a vital step in the new culture we want to achieve for our great sport."