Compensation should be paid without delay if devolved government is not restored at Stormont after the summer, child abuse victims said.
Survivors of wrongdoing at residential homes dating back decades urged Northern Ireland Secretary James Brokenshire to establish a redress scheme without delay if powersharing is not re-established in the coming months.
The Historical Institutional Abuse (HIA) inquiry has recommended compensation worth up to £100,000 for the worst affected.
Margaret McGuckin, who suffered abuse as a child at Nazareth House children's home in Belfast, said: "Today we put the Secretary of State on notice that we expect urgent action from him to establish a redress scheme which meets the needs of victims, should Stormont not be up and running again after the summer.
"Victims of child abuse have been waiting their whole lives for justice. Now they have been hit with further uncertainty and no government, just when they need it most. For abuse survivors, justice delayed truly is justice denied.
"That is why the UK Government must deliver if the Northern Ireland Government cannot."
The inquiry's report was published in January, just days after the collapse of the powersharing Executive at Stormont.
That has meant there have been no ministers to act on the recommendations contained in the report.
Those included state-backed compensation payments of up to £100,000 for those who experienced the most severe abuse and were transported to Australia under a controversial migrant scheme, down to £7,500 at a minimum.
The chairman of the public inquiry has already requested Mr Brokenshire implement the recommendations in his report.
Sir Anthony Hart said his report was both widely supported in the previous Assembly earlier this year and the subject of an assurance from the Prime Minister that it would be acted on.
His inquiry found evidence of widespread mistreatment.
Ms McGuckin added: "Right now, we need officials from the Executive Office to sit down with victims to co-design a redress scheme which meets the needs of survivors, rather than simply relying on the recommendations in the inquiry report, which fall short in a number of significant ways."
A spokesman for the Northern Ireland Office (NIO) said the Secretary of State was very moved by what the victims and survivors had to say.
"He was very clear the UK Government condemns any form of abuse of children, and any tolerance by people in positions of authority of such activity by others is abhorrent."
He said Sir Anthony's report was commissioned by the Office of the First and Deputy First Minister (OFMDFM) and was therefore a devolved matter.
"However, the Secretary of State fully recognises the frustration felt by victims and survivors at the lack of progress in taking it forward due to the suspension of the devolved administration.
"He is urging the parties to get back around the table as a matter of urgency to restore the Executive so that priority issues such redress and support for victims and survivors of child abuse can be properly considered and resolved."