An error which led cops to wrongfully stop and search paramilitary suspects could cost the force more than £50,000.
More than 100 republicans and loyalists were temporarily detained over a 12-day period last summer under anti-terror laws.
Derry New IRA chief Thomas Mellon is understood to be among this number.
A technical error meant that the stop-and-searches were unlawful as the paperwork had not been signed by a senior officer with the proper authority.
More than 100 compensation claims were lodged with the PSNI, which wrote to those affected last week offering individual payouts of £150.
But this has been rejected by the claimants, with legal sources telling Sunday Life they can expect payments of at least £500.
If so, this would bring the overall compensation bill for the PSNI to more than £50,000.
In some cases, not everyone illegally stopped and searched by police officers was a suspected paramilitary.
Relatives of dissident republicans and loyalists were among the 115 subjected to the unlawful action, with three aged under 18. Last December, the PSNI sent a written apology to those affected. Clarifying the mistake, a spokesperson said: "An error occurred because it was considered and signed by an individual who was an acting Assistant Chief Constable, rather than being temporarily promoted to the role.
"We have written to those individuals involved to inform them that the stop-and-searches were invalid and to apologise for any inconvenience caused."
Police have the power to conduct stop-and-searches under the Justice and Security (Northern Ireland) Act (2007).
This allows them, without the need of reasonable suspicion, to detain individuals suspected of involvement in terrorism or who they believe present a serious risk of violence and disorder.
However, approval for this must be signed off for a period of up to two weeks at a time - something which did not happen last summer.
After realising the mistake it had made, the PSNI referred itself to the Police Ombudsman and the Independent Reviewer of Justice and Security as part of "transparency around the powers".
A force spokesperson said: "As a police service, we use stop-and-search only when necessary for the protection of our community.
"We welcome the strict scrutiny and accountability that is in place to ensure the powers are used properly."
Having to pay out tens of thousands of pounds in compensation for unlawful stop-and-searches is the latest in a line of blunders to embarrass the PSNI.
Chief Constable Simon Byrne came in for heavy criticism when his officers broke up a small memorial service for the victims of the Sean Graham's betting shop massacre just days after cops watched 40 UVF men put on a show of strength in east Belfast.
The failure of the PSNI to tackle paramilitary funerals that breach coronavirus regulations also led to allegations of two-tier policing.
It was revealed before Christmas that the force was to pay out £875,000 in damages to journalists Trevor Birnie and Barry McCaffrey, who were wrongfully arrested over material that appeared in a documentary they produced on the Loughinisland massacre.