Sydney teenager Abdullah Elmir, otherwise known as the Ginger Jihadi, tried to recruit other teenagers in the Bankstown area to the Islamic State (IS) group, according to a former youth worker.

Sarkis Achmar, who was assistant manager at the Bankstown Multicultural Youth Service (BMYS) for five years, told 702 ABC Sydney that Elmir tried to preach to a group of youths at an outreach event organised by another welfare organisation.

"There were groups of men who were in traditional Islamic clothes [and] they were getting the younger people, like Elmir, to come in between the crowd and they'd start preaching to them," he said.

Mr Achmar said he intervened when Elmir started telling the boys, aged 13-16, that they would go to hell if they did not convert to Islam.

Elmir made international headlines last year when he appeared in an IS propaganda video directed at Prime Minister Tony Abbott.

The former Condell Park High School student disappeared in June 2014.

It is believed he travelled to Turkey and then crossed the border to Syria to join IS.

Mr Achmar said he tried to reach out to Elmir when he saw him around Bankstown but he was always under the watchful eye of older men.

"We ended up sort of breaking that barrier and, every now and again, having conversations with him, but he was hardly ever alone," he said.

"When we did speak, when he was alone those very few times, he would let his guard down and you could see that there was this confusion in him."

Mr Achmar said Elmir was yearning to belong to something but efforts to de-radicalise him failed.

"In the end he was just too embedded and too involved [in Islamic extremism], and when I saw him on TV it absolutely broke my heart," he said.

Other Sydney teenagers at risk of radicalisation

Mr Achmar is concerned that other young people in the Bankstown area are still being radicalised.

"It's definitely still brewing in Bankstown and brewing in other places as well," he said.

"You will see that they will try to do an act [of terrorism] on Australian soil because, if you look at history and what's happened overseas in every other country, it's what they do.

"It's all about instilling fear and having ownership."

Mr Achmar left Bankstown Multicultural Youth Service because he said he was frustrated with the way Government funding was being allocated for de-radicalisation programs.

"Services coming from outside are putting their hands up [for government funding] yet I did not see them interact with these kids on the streets and pull them away from the clutches of these people."

Mr Achmar said there should be a greater focus on strengthening community interaction and how everyone, not just Muslims, can deal with people radicalising young people.

