diff --git a/core/api/src/main/java/org/onosproject/net/flow/criteria/PiCriterion.java b/core/api/src/main/java/org/onosproject/net/flow/criteria/PiCriterion.java
index 2ba0bc8..23102dd 100644
--- a/core/api/src/main/java/org/onosproject/net/flow/criteria/PiCriterion.java
+++ b/core/api/src/main/java/org/onosproject/net/flow/criteria/PiCriterion.java
@@ -94,7 +94,7 @@
 
     @Override
     public String toString() {
-        StringJoiner stringParams = new StringJoiner(", ", "{", "}");
+        StringJoiner stringParams = new StringJoiner(", ");
         fieldMatchMap.forEach((key, value) -> stringParams.add(value.toString()));
         return stringParams.toString();
     }
diff --git a/core/api/src/main/java/org/onosproject/net/flow/instructions/PiInstruction.java b/core/api/src/main/java/org/onosproject/net/flow/instructions/PiInstruction.java
index 5db8a84..3558bd5 100644
--- a/core/api/src/main/java/org/onosproject/net/flow/instructions/PiInstruction.java
+++ b/core/api/src/main/java/org/onosproject/net/flow/instructions/PiInstruction.java
@@ -19,10 +19,10 @@
 
 import com.google.common.annotations.Beta;
 import com.google.common.base.Objects;
+import org.onosproject.net.pi.runtime.PiActionGroupId;
+import org.onosproject.net.pi.runtime.PiActionGroupMemberId;
 import org.onosproject.net.pi.runtime.PiTableAction;
 
-import static java.lang.String.format;
-
 /**
  * Representation of a protocol-independent instruction.
  */
@@ -75,9 +75,9 @@
     public String toString() {
         switch (tableAction.type()) {
             case ACTION_GROUP_ID:
+                return "GROUP:" + ((PiActionGroupId) tableAction).id().toString();
             case GROUP_MEMBER_ID:
-                // e.g. PiActionGroupId(1)
-                return format("%s{%s}", tableAction.getClass().getSimpleName(), tableAction.toString());
+                return "GROUP_MEMBER:" + ((PiActionGroupMemberId) tableAction).id().toString();
             default:
                 return tableAction.toString();
         }
diff --git a/core/api/src/main/java/org/onosproject/net/pi/runtime/PiAction.java b/core/api/src/main/java/org/onosproject/net/pi/runtime/PiAction.java
index bba3338..24655b6 100644
--- a/core/api/src/main/java/org/onosproject/net/pi/runtime/PiAction.java
+++ b/core/api/src/main/java/org/onosproject/net/pi/runtime/PiAction.java
@@ -17,7 +17,6 @@
 package org.onosproject.net.pi.runtime;
 
 import com.google.common.annotations.Beta;
-import com.google.common.base.MoreObjects;
 import com.google.common.base.Objects;
 import com.google.common.collect.ImmutableMap;
 import com.google.common.collect.Maps;
@@ -96,9 +95,7 @@
     public String toString() {
         StringJoiner stringParams = new StringJoiner(", ", "(", ")");
         this.parameters().forEach(p -> stringParams.add(p.toString()));
-        return MoreObjects.toStringHelper(this)
-                .addValue(this.id().toString() + stringParams.toString())
-                .toString();
+        return this.id().toString() + stringParams.toString();
     }
 
     /**