An Australian man who fought against the Islamic State in Syria has been allowed back into the country.

Queensland man Ashley Dyball, 23, was deported to Melbourne, Australia from Germany on Saturday night. He arrived in the country on Sunday, where he was interviewed by police and released without charge, according to his father, Scott Dyball.

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Dyball claims he has been fighting with Syrian Kurdish forces, the People's Protection Units (YPG), against the Islamic State since he left Australia in May. The United States supports the YPG and it is not listed as a terrorist organisation in Australia.

Ashley Dyball joined the fight with Kurdish forces in May. Image: Facebook / Ashley Dyball

Under the Australian foreign fighter law, it is illegal for anyone to fight overseas except with government forces.

"Australians have been consistently warned that by becoming involved in overseas conflict they are putting their own lives in mortal danger," an Australian Federal Police spokesperson told Mashable Australia via email.

"The Australian Federal Police is aware that an Australian national has arrived in Australia," the spokeperson added. "The public can rest assured that any Australian who is identified as a threat to security will be investigated by the relevant agencies."

Ashley Dyball and Reece Harding, before he was killed. Image: AAP Images

Dyball's lawyer, Jessie Smith, told radio station 3AW there is still a chance he will be charged, but she believes there is a legitimate defence.

"We see the greater claim that the YPG constitutes a government armed force which is a defence under the foreign fighter legislation," said Smith. Mashable Australia has contacted the Australian Defence Department for comment.

Dyball was arrested in Germany during a break from fighting and detained at the Eisenhuttenstadt Detention Centre. He wrote on Facebook on Dec. 4 that he had been charged "as a terrorist." Two days later, he arrived home in Melbourne where his family and friends, who have been supporting his mission, greeted him at the airport wearing yellow.

Ashley Dyball is greeted by his father Scott at Melbourne Airport. Image: AAP Images

"I’m really proud of him and what he has done," his mother Julia Dyball told media at the airport. "He is safe now and is home. It comforts us that the Australian government sees him as a hero. No charges have been laid at this time."

"He was with them for a few hours, he was questioned and he was released without charge," his father, Scott, added.

He then said there needs to be a distinction by the government between a foreign fighter and an ISIS fighter, and the law needs to be changed to reflect this.

"It has to be changed, how can you have evil and good and say it is the same thing," he said.