It is due to happen in May at the sites at Blacks Road, Sprucefield, Dundonald and Cairnshill.
Regional Development minister Danny Kennedy said he had to make the decision due to major cuts to funding.
And the reduction in the department's budget also means only the worst potholes on Northern Ireland's roads will now be repaired, it has confirmed.
The DRD minister said his department is facing a cut of £60m in its budget in the financial year 2015/16.
"I have had no other option but to make savings wherever I can find them," he said.
"Unfortunately this includes suspending the security and guarding arrangements at four park and ride sites."
The BBC understands that during the four years the Cairnshill park-and-ride facility has been running, no cars have been stolen from the site.
A heated and covered waiting area for customers using the service at Cairnshill is also set to close in May.
The DRD confirmed that funding cuts have also left TransportNI unable to provide a full road maintenance service.
Pothole repair will be now be carried out on a reduced scale, and no budget exists for salting roads next winter.
Workers have been told that each depot's budget for materials will be cut to £50 per day, according to one union.
Unite, which represents TransportNI employees, claims this threatens the safety of road users.
The minister told the DRD committee last week that only £13m was available for TransportNI to cover the cost of street lighting, patching materials and salt, external contractors, fleet maintenance and fuel.
The cost of all those services, he added, is normally over £40 million.
TransportNI - previously named Roads Service - has said maintenance staff will be used on tasks that do not require the purchase of materials.
The DRD confirmed that while there was no current budget for salting roads, it was "still planning to provide a winter service."
Unite say the department is relying on a reallocation from a future monitoring round for this funding.
Gareth Scott, Unite's regional officer with responsibility for TransportNI employees, said the situation was "intolerable".
"The impact of these cuts could cost lives throughout Northern Ireland.
"TransportNI workers will be impacted through likely reductions in staff, work and pay."
Security and guarding is to be withdrawn at four park-and-ride schemes operating on the outskirts of Belfast.