The parents of a Queensland man who has returned home after fighting against the Islamic State group in Syria have criticised Australia's foreign fighter laws, saying their son is a "hero in everyone's books".

Key points: Dyball released without charge after questioning by AFP

Dyball released without charge after questioning by AFP Anti-IS fighter's parents say he is a hero

Anti-IS fighter's parents say he is a hero Lawyer says Dyball can claim defence of serving foreign government

Ashley Dyball left his home in Brisbane in May this year to join a Kurdish military campaign against IS in northern Syria, and was arrested in Germany earlier this week while taking a break from the battlefield.

Mr Dyball — also known as Mitchell Scott — touched down in Melbourne last night, where he was greeted by Australian Federal Police officers and questioned for several hours.

His lawyer Jessie Smith said he was "interviewed, released without charge pending further enquiry".

Mr Dyball flew into Brisbane this morning with his parents, who said they were proud of their son.

"He's glad to be home. He's very thankful for all the supporters, not only just in Australia but around the world, he's got so much support," his father Scott Dyball said.

Mr Dyball posted on Facebook that after "feeling as wanted as Justin Bieber" he was glad to be home, but was "still currently under investigation".

"Also if anyone knows of work please message me as I want start work asap just something easy going for a while. Thank you everyone for your support it means a lot," he wrote.

Mr Dyball had been fighting against IS forces with a Kurdish militia called the YPG in northern Syria and risks prosecution under Australian foreign fighter laws, which forbid entering a foreign country with the intention of taking up arms.

Speaking at Brisbane airport, his father criticised the laws.

"How can you have evil and good and say it's the same thing? It's not. It's not the same thing," he said.

"And today it's not just for Ashley, but Harding... and to me it's cleared their names as well. And they're heroes in our books. In everyone's books."

He was referring to Gold Coast man Reece Harding, 23, who was killed in June when he stepped on a landmine while fighting for the Kurdish forces in Syria.

Ashley Dyball's mother Julia Dyball said she was proud of her son's efforts to help Kurdish fighters dismantle landmines.

"Countless people and children that have been killed by landmines. And I don't see what's so criminal about dismantling landmines so people can return home," she said.

Dyball 'can claim defence of serving foreign government'

Sorry, this video has expired Anti-Islamic State fighter Ashley Dyball arrives back in Brisbane

Scott Dyball earlier appealed to Prime Minister Malcolm Turnbull not to proceed with prosecution against his son.

"This is wrong, what the Government is trying to do to him is wrong," Mr Dyball said.

"The charges are just so ridiculous, they should be dropped. The law was unclear at the time, if they were clear the boys would not have gone.

"All we are asking is just an amnesty."

Ashley Dyball returned to Australia on Sunday evening. ( Facebook )

Ms Smith said Mr Dyball could claim the defence that he was engaged in the armed services of a foreign government.

"Mr Dyball could claim this defence due to Kurdish autonomy in Syria," she said.

She also said there was a public interest argument against prosecuting citizens fighting terrorists.

"There is also a separate and quite pressing public interest argument against prosecuting citizens who have been on the front line against Islamic State," Ms Smith said.

Mother of fellow Australian YPG fighter supporting Dyball family

Reece Harding's father Keith said it was of some comfort to see Mr Dyball return home.

"That was always our fear — that Ashley would come back like Reece — so it is a relief that he is home in one piece, that is for sure," Mr Harding said.

Ashley Dyball's parents Scott and Julia Dyball (L) with Michelle Harding (R) — mother of Reece Harding who was killed when he stepped on a landmine in Syria. ( ABC: Lexy Hamilton Smith )

Michelle Harding, Reece's mother, has formed a bond with the Dyballs and recently travelled to Syria to help them try to bring their son home alive.

"I don't want anyone else to be in our position [of losing a son]," Ms Harding said.

"When they went over there they knew the laws were in place but thought they were for [IS] terrorists.

"But, because the Government was very wishy-washy on it, people had gone over in the role our boys had gone over, and came back — they weren't prosecuted.

"There was no indication they were going to apply it to people fighting against [IS]."

She said she wanted the Prime Minister to "do the right thing".

"Don't make him a scapegoat because you do not want to lose face," Ms Harding said.