Concerned Muslim community leaders and members were lining up to help the authorities on Monday as news broke that an Islamic Shahada flag had been held up at the window of the Lindt cafe during the siege.

Within minutes The Grand Mufti of Australia, Dr Ibrahim Abu Mohammed, had offered to go to the site to speak to the man and convince him that what he was doing was wrong.

Dr Abu Mohammed offered his services to negotiate by phone or in person at the cafe in a bid to bring the situation to a peaceful conclusion.

He and other Sydney sheikhs made repeated offers during the day offering any type of support they could give or that might be needed.

"We wanted to help in any way we could, we also saw it as our duty to do that," said a spokesman for the Mufti.

Other Muslim leaders also rushed to help; community members offered to go in to talk to the man in whatever language he preferred.

Former Guantanamo Bay detainee Mamdouh Habib, who knew Man Haron Monis, for some time rang police and security agencies to offer his help saying he had had a lot of contact with him in the past and was willing to try and calm him.

"He was a sick man," said Mr Habib.

"I knew him and I used to speak with him to try and calm him down," Mr Habib told Fairfax Media. "I was willing to try and do something."

Community member Rebecca Kay also offered her services as a translator or a community person believing she might be able to help him see what he was doing was wrong.

"We felt the only people that could get through to him on a religious level or a cultural level was a member of the community," said Ms Kay.

"We wanted to do our part to bring safety and peace back to this country."

The one thing members of the Muslim community were asked to do yesterday was to find an IS flag to give to the gunman.

Three prominent people were asked separately to try and find a flag but none of them had any success.

The Muslim community were also receiving messages of support from around the world on Tuesday including from Shahid Malik, who was the first Muslim in the UK to become a government minister.

Mr Malik has praised the response of Australians on social media following the Sydney café siege. In particular, he said he felt inspired by the #Illridewithyou campaign on twitter, which encourages Muslims to be unafraid to wear symbols of their religious belief such as the head scarf and non-Muslims to support those choices.

"The campaign represents all that is great about humanity and I feel truly inspired by the reaction of so many Australians. We must always remember that the objective of those that commit such heinous acts is to drive wedges in our community in the hope of creating division and discord. The incredibly mature and common sense approach thus far will ensure they do not succeed."