Australia’s most decorated soldier Ben Roberts-Smith has broken a long public silence over rumours and allegations of misconduct, rejecting them as “malicious” and deeply troubling.

The 39-year-old former Special Air Services trooper is the subject of detailed reporting by Fairfax Media including allegations that he assaulted an unarmed detainee in Afghanistan in 2010, bullied junior troopers in his patrol and approved the questionable killing of a young Afghan man who had happened upon an SAS observation post.

But the report also delved into an aspect of the Victoria Cross recipient’s personal conduct, with accounts of an extramarital affair with a female lawyer that ended in April this year with allegations of “an act of domestic violence” being reported to police.

In a written statement, Mr Roberts-Smith vigorously denied the allegations.

Victoria Cross winner Ben Roberts-Smith during his days in Afghanistan. Photo: AWM

“I unequivocally deny any physical abuse of any woman at any time ever,” he wrote.

“I have not at any stage been interviewed by police about any purported complaint by any woman.”

More broadly, he described the Fairfax Media reports as “a catalogue of lies, fabrications and misrepresentations”.

“It is the culmination of many months of malicious and highly damaging allegations, all of which will be vigorously defended,” he wrote.

The ABC has been told the soldier-turned-business-executive for Seven West Media intends to sue for defamation in the Federal Court.

Questioned about the report of the “domestic violence” incident, Prime Minister Malcolm Turnbull said he was “aware of the allegation” but could not comment on “specific matters, because they are being dealt with by the police”.

“This is a serious matter. These are serious allegations. They have to be dealt with by the police in the appropriate way,” Mr Turnbull said.

While the Fairfax Media report directly attributed alleged mistreatment and abuse to Mr Roberts-Smith, it is not the first to publish accounts of serious misconduct by a number of soldiers within special forces units that served at high tempo in Afghanistan.

Stories of possible unlawful killings by elite Australian soldiers in Afghanistan bring into sharp focus the question of what went wrong inside Australia’s special forces community.

The ABC has previously reported how cultural problems were uncovered by multiple investigations — the most powerful, by the Australian Defence Force Inspector-General, is soon to be completed.

The investigations have ruptured the normally closed ranks of the SAS and special forces community and pitted former soldiers against each other through written complaints, sworn statements, media leaks and strange campaigns of personal retribution that have included sending anonymous letters and threats to one another.

Throughout the upheaval, Australian War Memorial director Brendan Nelson has been a steadfast supporter of Mr Roberts-Smith and SAS soldiers who fought in Afghanistan.

Dr Nelson bemoaned the latest Fairfax Media reporting.

“I have to ask where is the national interest in what’s being done here?” he said.

“It diminishes my respect for the media.”

-ABC