diff --git a/src/core/thread/network_data_leader_ftd.cpp b/src/core/thread/network_data_leader_ftd.cpp
index a4fa20a49..c3f219a9c 100644
--- a/src/core/thread/network_data_leader_ftd.cpp
+++ b/src/core/thread/network_data_leader_ftd.cpp
@@ -1319,9 +1319,34 @@ void Leader::HandleNetworkDataRestoredAfterReset(void)
 {
     const PrefixTlv *prefix;
     TlvIterator      tlvIterator(GetTlvsStart(), GetTlvsEnd());
+    Iterator         iterator = kIteratorInit;
+    ChangedFlags     flags;
+    uint16_t         rloc16;
 
     mWaitingForNetDataSync = false;
 
+    // Remove entries in Network Data from any un-allocated Router ID.
+    // This acts as a safeguard against an edge case where the leader
+    // is reset at an inopportune time, such as right after it removed
+    // an allocated router ID and sent MLE advertisement but before it
+    // got the chance to send the updated Network Data to other
+    // routers.
+
+    while (GetNextServer(iterator, rloc16) == kErrorNone)
+    {
+        if (!Get<RouterTable>().IsAllocated(Mle::RouterIdFromRloc16(rloc16)))
+        {
+            // After we `RemoveRloc()` the Network Data gets changed
+            // and the `iterator` will not be valid anymore. So we set
+            // it to `kIteratorInit` to restart the loop.
+
+            RemoveRloc(rloc16, kMatchModeRouterId, flags);
+            iterator = kIteratorInit;
+        }
+    }
+
+    IncrementVersions(flags);
+
     // Synchronize internal 6LoWPAN Context ID Set with the
     // recently obtained Network Data.