The Islamic Women's Council says the Christchurch mosque shootings might not have happened, if it weren't for the failures of multiple government agencies - particularly the security intelligence service and police.

The council has taken the unusual step of releasing its submission to the Royal Commission of Inquiry into the Christchurch mosque attacks - ahead of the commission's final report-back date.

In the aftermath of the shootings at the Al Noor and Linwood mosques on March 15 last year, the Royal Commission was ordered to investigate what government agencies knew about the attacker before the shootings.

The commission will also look into what, if anything, they did with that information; what measures agencies could have taken to prevent the attack; and what measures agencies should take to prevent such attacks in the future.

Brenton Tarrant has pleaded guilty to 51 charges of murder, 40 charges of attempted murder and one charge under the Terrorism Suppression Act.

He is due to be sentenced on 24 August in the High Court at Christchurch - a hearing that could last at least three days.

The commissioners' final report is due at the end of this month, but the Islamic Women's Council has decided to make its submission public ahead of that.

The 170-page submission includes almost 40 recommendations.

The submission outlines the council's interactions with a host of government agencies in recent years, including the Security Intelligence Service, the Human Rights Commission and the Race Relations Commissioner, the Department of Prime Minister and Cabinet, the Department of Internal Affairs and the Office of Ethnic Communities.

The council said the government failed to support and protect the Muslim community and prevent the 15 March attack.

"In the years prior to 15 March 2019 there were repeated major public service delivery failures in relation to government dealings with and responsibilities towards the Muslim community in Aotearoa New Zealand," the submission said.

"It is likely that, but for the failures (particularly of the security services and police), the horrific events of 15 March, 2019, might not have occurred.

"It is certain that but for the failures of the other public sector agencies there would have been greater support and protection of the Muslim community before 2019 as the pressure on them grew and after, when the trauma and shock had to be dealt with."

The submission details a number of meetings council members had with various representatives from the Security Intelligence Service, including its head Rebecca Kitteridge.

The council said at those meetings, its message was clear: "It was that the government had failed and was failing the Muslim community. There was a lack of support on the preventative side. There was a rise in hate and hate groups in New Zealand".

The council went on to say that from their interactions, there was no indication that the alt-right was under any, let alone serious or similar scrutiny and surveillance as the Muslim community before 15 March, despite the increasing Islamophobia and hate speech directed as Muslims in New Zealand and the rise of the alt-right in Europe and the United States and the many terrorist attacks by the alt-right".

The council said the Security Intelligence Service could not have been surprised by what happened on 15 March, because the council had warned them about growing anti-Muslim sentiment.

"Their inaction had had the most egregious consequences," the submission said.

"If [the council] had been taken seriously the SIS would have kept an eye out for activity by white supremacists. They managed to catch young Muslim men sharing ISIS videos in New Zealand and have had them prosecuted. To discover this, they were spying on the young men online. Why was there no equivalent spying on young white supremacist men?"

The council said the police failed in not developing a national strategy to deal with threats against Muslims and mosques.

Among the council's recommendations, it wants an apology for the failings of the SIS and government agencies in relation to the attack.

It also wants reparations paid to those who have suffered economic loss, that is not covered by ACC or any other workplace scheme.