Keysar Trad, from the Islamic Friendship Association of Australia,  and nine other Muslim leaders were in a meeting this morning with federal and state police when they heard about the siege.

"The police were just informing us about charges that were going to be laid against two men who were involved in the raids in September," Trad said.

"When news of the siege came through there was speculation in the room that it could be linked to that, that perhaps it was a parent of one of the men who was being charged. But we really don't know."

Muslim community figure Rebecca Kay said the siege would probably intensify anti-Islamic sentiment. "You are already seeing stuff on social media, with people saying 'Deport all Muslims'," she said.

"After the new security laws were introduced, we tracked attacks on Muslims through Sydney, and we found that there were five to seven attacks per day for three week period.

"Cars being vandalised, women being punched, being spat on or verbally abused. That will probably increased now in the lead up to Christmas. It's all people, are going to be talking about."

Ms Kay said she has been in contact with counter-terrorism police, "and offered my services. The hostage-taker guys are nut-jobs; I want to ask them, 'What do you hope to achieve for Islam out of this?'."

Kuranda Seyit , from the Forum on Islamic Relations said his group was meeting now to discuss the incident and a strategy for the community to deal with it.

"We don't know what the demands are, the motivations, and until we do it's very hard to respond," he said.

"I don't want it to have a disastrous end," said Mr Kuranda.

"I think it will most likely turn out to be a disenfranchised, unhappy person. I don't think it is a terrorist attack. If it was, it would have been much better planned."