More than £130m in special payments is to be given to police officers retiring in the next two years, according to figures obtained by the BBC.
The one-off payment was negotiated as part of the review into NI policing, completed in 2001 by former Hong Kong governor Chris Patten.
He was brought in to reform the RUC as part of the Good Friday Agreement.
Figures for the next two years show 1,100 officers will receive pensions at a cost of £132m.
This includes around 700 police officers who will receive around £88m.
Just over 400 full-time reserve officers will also leave at an estimated cost of £44m.
BBC NI's home affairs correspondent Vincent Kearney said the Patten reforms included "a generous retirement package that encouraged thousands of long-serving officers to leave and make room for new recruits, 50% of whom have to be Catholic".
He added: "Around 4,500 have already left the police since the scheme was introduced in January 2001, and the total cost is expected to be well over half a billion pounds."
It is understood the average one-off payment to a constable is £95,000, while some senior officers have been given up to £500,000.
The DUP's policing board member Ian Paisley Jnr claimed the PSNI has been "robbed of experienced officers".
"We're stripping the police of experienced and skilled officers at a critical time and we're creating a situation where we're spending hundreds of millions of pounds getting rid of experienced officers and then saying we don't have the budget. It does not add up."
The SDLP, which helped negotiate the policing reforms, said it was "a price worth paying".
Policing spokesman Alex Attwood said 26% of police officers are now Catholic, compared to 8% of RUC officers.
"We now have a situation where we're not that short of having a truly representative and fully accountable police service," he said.
"There's been a heavy price to pay in the loss of officers and the cost, but it's entirely priceless that we have in the north now the police service that has the support across the political parties and the community."