The PM has issued a powerful national apology for the "abomination" of child sex abuse.

Prime Minister Scott Morrison says Australia must acknowledge the long and painful journey of sexually abused children and say sorry.

Hundreds of survivors came to Canberra on Monday to hear a national apology to victims and survivors of child sexual abuse exposed in a royal commission.

“Today as a nation we confront our failure to listen, to believe, and to provide justice … we say sorry,” Mr Morrison told parliament.

He said it was a day to confront key questions: “Why weren’t the children of our nation loved, nurtured and protected? Why was their trust betrayed?

“Why did those who know cover it up? Why were the cries of children and parents ignored? Why was our system of justice blind to injustice? Why has it taken so long to act? Why were other things more important than this, the care of innocent children? Why didn’t we believe?”

He said nothing could be done to right the wrongs inflicted on children.

“Even after a comprehensive royal commission, which finally enabled the voices to be heard and the silence to be broken, we will all continue to struggle,” he said.

“So today, we gather in this chamber in humility, not just as representatives of the people of this country, but as fathers, as mothers, as siblings, friends, workmates and, in some cases, indeed, as victims and survivors.”

Mr Morrison acknowledged the work of former prime minister Julia Gillard who set up the inquiry, which heard from 17,000 survivors.

The government plans a national museum to raise awareness and understanding of the impacts of child sexual abuse, displaying the history so the nation does not forget the untold horrors they experienced.

A research centre will look to raise awareness and understanding of the impacts of child sexual abuse, support help seeking and guide best practice for training and other services.

The government will also commit to reporting every year for the next five years on the progress of the royal commission’s recommendations.

It has already accepted 104 of the 122 recommendations handed down by the royal commission, with the other 18 being examined in consultation with states and territories.