A £40m holiday pay bill being faced by the Police Service of Northern Ireland (PSNI) “could rise”, the solicitor representing the claimants has said.
John McShane said the pay judgement was based on figures provided by the PSNI.
It would be “professionally negligent” of him not to “properly investigate” the figures, said the solicitor.
He added that with remedy hearings it could be 10 years before payments are made.
“If I was recommending my clients to accept it, I am recommending that acceptance on a concrete financial basis,” Mr McShane told BBC News NI.
Class action was brought by a group representing more than 3,700 police officers and civilian staff.
The Court of Appeal in Belfast upheld a 2018 tribunal finding that they are owed money for a shortfall in holiday pay dating back 20 years.
‘Police already under pressure’
Miscalculations arose after holiday pay was based on basic pay and did not include overtime.
The original tribunal made its decision in November 2018. At that stage, the bill was up to £30m.
However, the figure could now be £40m after judges held that holiday pay should be calculated on the basis of actual annual working days.
It is understood individual payments could be in the region of £10,000 on average.
Claire Sugden, a former Stormont justice minister, said the sum was “a significant amount of money” and could potentially affect public services in Northern Ireland.
“Not least just the police – police are already under pressure and I think to find this money in any other part of their budget will be difficult.,” she said.
She suggested the cost of the bill could be financed by the Treasury.
‘Seeking legal advice’
On the difficulty in meeting the cost of the payments, Mr McShane said: “I completely sympathise with the circumstances but this wasn’t caused by my clients.
“This was a situation where they are properly entitled to be paid, where they are lawfully entitled to be paid.”
The appeal was brought by the PSNI Chief Constable George Hamilton and the Police Authority, now the Policing Board.
BBC News NI’s home affairs correspondent Julian O’Neill said it had challenged the period of time settlements should cover.
He said the dismissal of the appeal meant “what is owed must now be recalculated from as far back as 1998”.
The appeal court judge said that the “lead cases should now continue before the tribunal to a final determination”.
PSNI Assistant Chief Constable George Clarke said the PSNI was seeking further legal advice on the matter.