The Islamic organisation Hizb ut-Tahrir has denied any link to the Parramatta gunman while predicting the government would "milk the shooting" in an attempt to criminalise Islam.

Media outlets reported that 15-year-old Farhad Khalil Mohammad Jabar attended a Hizb ut-Tahrir lecture at Parramatta Mosque on Friday.

That afternoon, Jabar shot dead a police accountant, Curtis Cheng, before he was shot dead himself by police special constables.

"The alleged links of Farhad Jabar to Hizb ut-Tahrir are so groundless and absurd, they deserve naught but derision," the group said in a statement on Monday. Headed "media lies and criminalisation of Islam", the statement said Hizb ut-Tahrir did not deliver a lecture at the Parramatta Mosque on Friday. A mosque spokesman also said the sermon was not by Hizb ut-Tahrir.

Hizb ut-Tahrir, which seeks to establish an Islamic caliphate, has been criticised for not condemning violence committed by radicalised Muslims. But the group said its philosophy of non-violence was "clear as day".

"Actions like the Parramatta shooting are plainly wrong," it said. "In contrast, the Australian Government's foreign policy routinely employs the most callous of violence to further its economic and political interests in other parts of the world and the mainstream media chirps its supports like a well-trained parrot."

Hizb ut-Tahrir went on to say the "real cause of violence is western foreign and domestic policy".

"It is about time the Australian establishment assumed responsibility for all the violence and hate it has created.

"No doubt government authorities will milk this shooting to justify further insidious intervention in the Muslim community and further policing of Muslim youth."

Hizb ut-Tahrir, which is banned in some countries but not Australia, said it was launching a month-long campaign against government intervention in Muslim communities. On Sunday, it held a rally in the western Sydney suburb of Lakemba to protest against US and Russian airstrikes in Syria.

The Daily Telegraph reported that a sheik from the group, Ismail al-Wahwah, refused to comment on the Parramatta shooting.

Spokesman for Hizb ut-Tahrir, Wassim Dourehi, appeared on the ABC's Lateline program in October last year and refused to condemn acts of violence by Islamic State.

Mr Dourehi instead spoke about the violence of Western countries at war in the Middle East.