Sinn Fein has been blamed for blocking the publication of eligibility guidelines for a pension for Troubles victims at the last minute - a move that could scupper the scheme for a year.
Secretary of State Brandon Lewis was due to publish draft guidelines yesterday, but they failed to materialise.
The Northern Ireland Office has said this will now happen at a later date.
At the same time the Prime Minister was telling MPs that the controversy-hit compensation scheme is a "fair, balanced and proportionate way" of helping those injured during the violence. He urged Sinn Fein to "allow the scheme to go forward as soon as possible".
The scheme was supposed to open to applications on May 29, but has been delayed as Sinn Fein and the DUP argue over who can receive the pension.
While it excludes anyone injured by their own actions, it would potentially cover other people who had terror convictions.
However, a judge-led panel will be set up to examine on a case-by-case basis whether payments would be appropriate for people with convictions for serious offences.
Sinn Fein rejected the revised draft guidelines presented to all the political parties this week, saying they discriminate against former prisoners and go beyond what is in the legislation.
The Executive and the UK Government are also in a stand-off over who will pay for the scheme, estimated to cost around £100m.
Ulster Unionist justice spokesman Doug Beattie MLA said: "If we are at a stage where the Northern Ireland Office and Secretary of State won't release the guidance notes because of Sinn Fein's objections, what on Earth chance have we to get this victims' payment scheme moving forward?
"The solution is clear. If Sinn Fein is not willing to nominate a lead department to take this forward then the NIO should return the scheme back to themselves.
"The scheme is pointless if it's not being delivered and this is going to turn into a political argument that nobody wants.
"The only people suffering here are the victims, and with no end in sight we could be arguing about this for another year."
DUP Westminster leader Sir Jeffrey Donaldson raised the matter with Boris Johnson during Prime Minister's Questions yesterday.
Speaking in the Commons, Sir Jeffrey appeared to be under the impression that the guidelines had just been published. He said: "The Prime Minister will be aware that the Secretary of State for Northern Ireland has today published the guidelines for the special payments scheme for severely injured victims linked to the Troubles in Northern Ireland.
"The Prime Minister will also know that this House passed legislation which excludes those injured by their own hand. But the innocent victims have not yet been able to benefit from this scheme, not least because of the actions of Sinn Fein.
"Will the PM have his Government now commit to do all that they can to move this matter forward?"
Mr Johnson replied: "I think this scheme provides a fair, balanced and proportionate way of helping all those who suffered most during the Troubles and it's very important that Sinn Fein, along with all other parties, allow the scheme to go forward as soon as possible."
Kenny Donaldson, spokesman for Innocent Victims United, said: "If there continues to be a refusal to implement the law then sanctions must follow, or failing this, the UK Government must take a grip of this issue."
Shadow Northern Ireland secretary Louise Haigh said yesterday that it was "deeply disingenuous" of Mr Johnson to lay all of the blame for the delays in the pension scheme at Sinn Fein's door.
"This UK-wide scheme should be financed by the UK Government, but they haven't put up a penny," she tweeted.