diff --git a/agent/src/main/scala/za/co/absa/atum/agent/AtumContext.scala b/agent/src/main/scala/za/co/absa/atum/agent/AtumContext.scala
index 177c27936..501d805a3 100644
--- a/agent/src/main/scala/za/co/absa/atum/agent/AtumContext.scala
+++ b/agent/src/main/scala/za/co/absa/atum/agent/AtumContext.scala
@@ -18,6 +18,7 @@ package za.co.absa.atum.agent
 
 import org.apache.spark.sql.DataFrame
 import za.co.absa.atum.agent.AtumContext.{AdditionalData, AtumPartitions}
+import za.co.absa.atum.agent.exception.AtumAgentException.PartitioningUpdateException
 import za.co.absa.atum.agent.model._
 import za.co.absa.atum.model.dto._
 
@@ -52,6 +53,10 @@ class AtumContext private[agent] (
    * @return the sub-partition context
    */
   def subPartitionContext(subPartitions: AtumPartitions): AtumContext = {
+    val overlap = atumPartitions.keys.toSet.intersect(subPartitions.keys.toSet)
+    if (overlap.nonEmpty) {
+      throw PartitioningUpdateException(s"Partition keys '$overlap' already exist. Updates are not allowed.")
+    }
     agent.getOrCreateAtumSubContext(atumPartitions ++ subPartitions)(this)
   }
 
diff --git a/agent/src/main/scala/za/co/absa/atum/agent/exception/AtumAgentException.scala b/agent/src/main/scala/za/co/absa/atum/agent/exception/AtumAgentException.scala
index 00196b84b..71825203c 100644
--- a/agent/src/main/scala/za/co/absa/atum/agent/exception/AtumAgentException.scala
+++ b/agent/src/main/scala/za/co/absa/atum/agent/exception/AtumAgentException.scala
@@ -40,4 +40,10 @@ object AtumAgentException {
    * @param message A message describing the exception.
    */
   case class HttpException(statusCode: Int, message: String) extends AtumAgentException(message)
+
+  /**
+   * This type represents an exception related to partitioning update.
+   * @param message A message describing the exception.
+   */
+  case class PartitioningUpdateException(message: String) extends AtumAgentException(message)
 }