Mr Hastie was called to give evidence in defamation proceedings launched by the Victoria Cross recipient over allegations he committed war crimes in Afghanistan, bullied colleagues, and assaulted his mistress.

The 43-year-old denies all the allegations reported by The Age, The Sydney Morning Herald and The Canberra Times, who are defending them as true.

Mr Hastie - who served as a captain in the Special Air Service Regiment between 2010 and 2015 and is now assistant minister for defence - on Friday told the Federal Court he had heard allegations from many people about Mr Roberts-Smith.

One man told him Mr Roberts-Smith punched him while they were deployed, while others recounted bullying and an incident where he allegedly shot a corpse.

He also came to believe Mr Roberts-Smith had been involved in an execution of an Afghan.

As whispers of misconduct by Australian forces in Afghanistan began to build, Mr Hastie recalled talking to his second-in-command in 2013 to set expectations about their next deployment.

"He said... 'I'm not going to Afghanistan to put dirt farmers on their knees and shoot them in the back of the head'," something Mr Hastie understood to be a reference to Mr Roberts-Smith.

While he doesn't recall raising allegations about Mr Roberts-Smith - with whom he had little direct contact - with his superiors, he said he did speak to them about a policy which he felt incentivised soldiers to take the law into their own hands on the battlefield.

Mr Roberts-Smith's lawyers have repeatedly suggested allegations against the war hero were made up by a small group of peers who were jealous of his military accolades.

But Mr Hastie listed 20 people who had suggested to him that Mr Roberts-Smith was a hypocrite - that "the outward facing picture of Mr Robert-Smith was at odds with his battlefield conduct".

It was a far cry from the initial impression he had of Mr Roberts-Smith, who had given Mr Hastie a tour of SAS facilities in 2009 before he joined the regiment.

"(He) met us at the door, wearing footy shorts, a pistol on his hip... (he) looked a million dollars, fit as a fiddle, confident," Mr Hastie told the court.

"I thought this is a unit I want to be part of.

"I started from a very high regard for Mr Roberts-Smith ... (but) I'm no longer proud of (him)."

However, Mr Hastie denied disliking him, saying his family prayed for him.

"I pity him."

"I don't want to be here ... this is terrible for our country. It's terrible for the SAS. It's terrible for the army.

"But until we deal with it, we can't move forward."

But Mr Robert-Smith's barrister, Arthur Moses SC, suggested Mr Hastie was a hypocrite.

He accused the politician of making off-the-record allegations about Mr Robert-Smith to reporters while making on-record comments about the need to respect the defence force investigation into the matters, all to raise his profile as an MP.

Mr Hastie denied the suggestion, saying he spoke up out of love for the SAS and a belief in the importance of investigative journalism, referencing a 2019 speech given by Mr Moses, the then-president of the Law Council.

"I must say I'm very sympathetic to your speech ... where you argue that public interest journalism is critical to a healthy democracy ... I think we share a strong view on this," Mr Hastie said.

Mr Moses also argued Mr Hastie had come to court to support newspaper publisher Nine's arguments because they were covering his legal fees in separate defamation proceedings, which could risk leaving him bankrupt and in danger of losing his seat in parliament.

"Do you feel that you have needed to come to court ... and make statements supportive of ... the respondents because of the assistance that they're providing you?" Mr Moses asked.

"Absolutely not," Mr Hastie said.

Mr Moses asked: "Do you agree that ... you are beholden to the respondents in this case because they are supporting you in that case?"

"No, I don't," he replied.

Mr Hastie will return as a witness on Monday.

Australian Associated Press