The Islamic council of Victoria has refused to condemn the actions of a man who was fatally shot after stabbing two anti-terrorism police, and has hit out at authorities for pre-empting the outcome of investigations into the tragedy.

Council secretary Ghaith Krayem has also criticised the government for adopting an "enforcement" approach to managing the threat of home-grown terrorism, describing underlying issues as social, rather than religious and in need of greater scrutiny.

"There needs to be no hint whatsoever that anything other than the complete truth about the events of yesterday are what comes out," Mr Krayem said, after branding police comments made immediately after the tragedy as "disappointing".

He acknowledged the need for information to be released to the public, but added: "We have a young man who is no longer with us and we have a family who today has woken up to some very terrible events and headlines which, quite frankly, at this stage there doesn't appear to be objective justification for."

Numan Haider, the 18-year-old who allegedly stabbed two officers during a meeting near the Endeavour Hills Police Station had been a person of interest to the anti-terrorism taskforce for months and was among those who recently had their passports suspended.

Police were investigating allegations he had unfurled an Islamic State flag in a suburban shopping centre and made inflammatory remarks about ASIO and the AFP on social media, in the lead-up to the confrontation.

"It is incumbent on us as a society not to forgo our own principals and values that make us who we are and one of those is the presumption of innocence, even for a deceased person," Mr Krayem said.

"I'm not going to condemn what he did because I don't know what he did and I think it's wrong for anybody to be condemning this young man until the full investigation takes place and we actually understand what occurred."

On Wednesday, Justice Minister Michael Keenan confirmed Mr Haider was a "known terror suspect", while Prime Minister Tony Abbott, speaking from Hawaii, said the incident had shown there were people in Australia "capable of very extreme acts".

Mr Krayem warned against making assumptions, saying that brandishing a flag and making disparaging comments about Australian agencies did not mean Mr Haider was a terrorist. Nor did being young, angry and immature, he said. "While I don't know the young man personally, I do know many young men at that age and they can be brash, they can be angry, they can be immature.  None of those things make him a terrorist."

More needed to be done to understand disaffected youths and bring them back into the community, rather than drive them further out by "treating them as criminals", he said.

"We can't just deal with these issues from an enforcement and a criminality perspective," he said.  "We've been doing enforcement for the last 15 years and we're in a worse situation in society than we were after 9/11."

However, Ekrem Fuldagli, leader of the Cyprus Turkish Islamic Community of Victoria, distanced moderate Muslims from those who might sympathise with extremist groups.

"The general public at large... are led to believe that these extremists are actually part and parcel of our religion. They're not with us," he told 3AW.

"I condemn [violent acts] completely.  "I want listeners to understand that we have been on Team Australia before the Prime Minister graduated from high school."

Victorian Premier Denis Napthine and Chief Commissioner Ken Lay called for calm from the community and warned against discrimination in the wake of the tragedy.  "It is not about faith, it's not about ethnicity, it is about the alleged behaviour of an individual," Dr Napthine said.

Mr Haider's death comes as Islamic leaders tell of a rise in attacks against Australian Muslims, including people being spat on, prams kicked and pigs heads impaled on crosses.

A joint statement released by diverse faith leaders, including the Grand Mufti of Australia, Dr Ibrahim Abu Mohamed, condemned violence being perpetrated in the name of religion overseas, including the Islamic State's recent call to arms from its overseas supporters.

"The recent call for violence from overseas, targeting Australia as well as other countries has no religious authority and must be rejected," the statement said.

"The sanctity of life is of paramount importance for all people of faith and to all people of goodwill."

Mr Krayem blamed "inappropriate language" from senior members of the Abbott government and recent "ill-informed comments" from Senator Jacqui Lambie, as well as increased terror alerts, for mounting anxiety and fear in the community.

Dr Napthine will continue to meet faith leaders in coming days and will discuss whether increased security is needed for religious institutions.

with Henrietta Cook