Fears have been voiced by a leading union that hundreds of civil servants could face redundancy.
The concerns were raised after it emerged 270 workers are to be redeployed in the Department of the Environment.
Earlier this year the department said staff identified for redeployment knew they had been selected and their names had been placed in a “priority surplus pool”.
The number of posts in Planning Service is currently 767.
Michael Robinson, from the public service union Nipsa, said it would be hard to find work for skilled staff in other departments.
“The administrative staff will first be redeployed into other administrative posts the professional staff will have to volunteer for regrading,” he told the BBC.
“If they cannot be found posts then they have been told very clearly there will a redundancy situation.”
The number of planning applications has fallen by 45% from 2004-05 when 36,593 were made.