In announcing the investigation at a press conference in Canberra, Chief of the Army, Lieutenant-General David Morrison, said the allegations being examined were "disgraceful" and "worse than the Skype scandal" that hit Defence in 2011.

General Morrison said he had already spoken and apologised to four of the women who were victims of the emails and imagery. He said there were several other victims.

"They were angry, they were concerned," he said.

There are also suggestions that illicit drug use may be involved.

The Army chief lamented that the email claims came after significant efforts to encourage women to join and stay in the Army.

''I'm appalled at this situation,'' General Morrison said.

General Morrison said that three Army members have already been suspended and are persons of interest to the NSW Police.

Five Army personnel are under consideration for suspension and evidence is being collected in relation to a further nine.

General Morrison told reporters that a broader group of about 90 Defence personnel - overwhelmingly from the Army - may be on the periphery of the group involved in the email exchanges.

He said the allegations involve the production and distribution of ''highly inappropriate'' material across both defence computer systems and the internet over the past three years.

In some of the messages that have been examined, there is a ''suspicion of reference to illicit drugs and no more than that at the moment''.

A spokesman for NSW Police said Kings Cross Local Area Command established Strike Force Civet in July 2012 to investigate the alleged exchange of offensive emails by Australia Defence Force personnel.

''The investigation into the activities of three ADF personnel has been finalised,'' he said.

''A brief has been prepared and forwarded to the Commonwealth Director of Public Prosecutions.''

'Worse than Skype scandal'

General Morrison said he was keeping an open mind about the investigations underway, but added "I view the allegations that are being made in the gravest light".

He said the claims brought the Army into disrepute and he was resolved that, if proven, every possible step would be taken to remove the perpetrators.

General Morrison said he was not able to go into detail about the emails and photos exchanged across the Defence system and public internet, but said they were explicit, derogatory and demeaning and ''repugnant to me''.

When asked if the latest allegations were a repeat of the Skype scandal, he was it was "worse".

The so-called ''Skype scandal'' refers to an incident in 2011 when a cadet, known as Kate, discovered her sexual encounter with another cadet had allegedly been streamed, without her consent, via Skype to other male cadets.

It prompted wide-ranging reviews into abuse within Defence, and calls for cultural change within the military.

General Morrison said the group under investigation involved officers and non-commissioned officers, including a lieutenant colonel, majors, captains and warrant officers.

It is understood that the female victims include ADF personnel, public servants and members of the broader public.

'Army is changing'

General Morrison said he was not able to answer how the matter came the attention of authorities.

But he said the Australian Defence Force Investigative Service (ADFIS) told ADF chief David Hurley about the matter on April 10.

General Morrison was overseas at the time but was told when he returned soon after. Defence Minister Stephen Smith was also informed at the time.

General Morrison said that Defence leadership no longer accepted the ''bad apple'' argument about behaviour within its ranks.

''The Army is changing and what you are seeing today is evidence of that change and my commitment to transparency.''

Sex Discrimination Commissioner Elizabeth Broderick, who led a recent review into the ADF's treatment of women, said she was appalled by the revelations.

"It's just totally unacceptable," she told ABC TV.

She said there were a lot of positive aspects of the Defence culture but said she had also heard "deeply distressing stories in certain pockets about highly sexualised work environments."

In a statement following General Morrison's press conference, Mr Smith said he strongly supported the Army chief's actions.

"I welcome the strong response that demonstrates in the post-ADFA Skype environment a zero tolerance for this type of behaviour," he said.

"The government and Defence leadership are committed to pursuing the reform necessary to ensure zero tolerance of inappropriate conduct."

Opposition defence spokesman David Johnston said that the allegations raised on Thursday were of ''great concern'' to the Coalition.

But although the allegations were serious, he said he had confidence ADFIS would investigate them thoroughly and properly.

Senator Johnston said he would seek an urgent briefing with the Chief of the Army to be kept updated with the progress of the investigations.

with Emma Partridge, AAP

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