diff --git a/src/core/thread/network_diagnostic.cpp b/src/core/thread/network_diagnostic.cpp
index 6f62461f6..05ef7bbc6 100644
--- a/src/core/thread/network_diagnostic.cpp
+++ b/src/core/thread/network_diagnostic.cpp
@@ -435,22 +435,8 @@ Error Server::AppendDiagTlv(uint8_t aTlvType, Message &aMessage)
         break;
 
     case Tlv::kChannelPages:
-    {
-        ChannelPagesTlv tlv;
-        uint8_t         length = 0;
-
-        tlv.Init();
-
-        for (uint8_t page : Radio::kSupportedChannelPages)
-        {
-            tlv.GetChannelPages()[length++] = page;
-        }
-
-        tlv.SetLength(length);
-        error = tlv.AppendTo(aMessage);
-
+        error = Tlv::Append<ChannelPagesTlv>(aMessage, Radio::kSupportedChannelPages, Radio::kNumChannelPages);
         break;
-    }
 
     case Tlv::kNonPreferredChannels:
     {
@@ -1172,6 +1158,14 @@ exit:
     return error;
 }
 
+void Client::ReadDiagData(DiagData &aDiagData, const Message &aMessage, const Tlv::Info &aTlvInfo)
+{
+    OffsetRange offsetRange = aTlvInfo.GetValueOffsetRange();
+
+    offsetRange.ShrinkLength(GetArrayLength(aDiagData.m8));
+    aDiagData.mCount = static_cast<uint8_t>(aMessage.ReadBytes(offsetRange, aDiagData.m8));
+}
+
 void Client::ParseMacCounters(const MacCountersTlv &aMacCountersTlv, otNetworkDiagMacCounters &aMacCounters)
 {
     aMacCounters.mIfInUnknownProtos  = aMacCountersTlv.GetIfInUnknownProtos();
@@ -1272,8 +1266,7 @@ Error Client::GetNextDiagTlv(const Coap::Message &aMessage, Iterator &aIterator,
                           "NetworkData array in `otNetworkDiagTlv` is too small");
 
             VerifyOrExit(tlvInfo.GetLength() <= NetworkData::NetworkData::kMaxSize, error = kErrorParse);
-            aDiagTlv.mData.mNetworkData.mCount = static_cast<uint8_t>(tlvInfo.GetLength());
-            aMessage.ReadBytes(tlvInfo.GetValueOffsetRange(), aDiagTlv.mData.mNetworkData.m8);
+            ReadDiagData(aDiagTlv.mData.mNetworkData, aMessage, tlvInfo);
             break;
 
         case Tlv::kIp6AddressList:
@@ -1344,10 +1337,7 @@ Error Client::GetNextDiagTlv(const Coap::Message &aMessage, Iterator &aIterator,
         }
 
         case Tlv::kChannelPages:
-            aDiagTlv.mData.mChannelPages.mCount =
-                static_cast<uint8_t>(Min(tlvInfo.GetLength(), GetArrayLength(aDiagTlv.mData.mChannelPages.m8)));
-            aMessage.ReadBytes(tlvInfo.GetValueOffset(), aDiagTlv.mData.mChannelPages.m8,
-                               aDiagTlv.mData.mChannelPages.mCount);
+            ReadDiagData(aDiagTlv.mData.mChannelPages, aMessage, tlvInfo);
             break;
 
         case Tlv::kMaxChildTimeout:
diff --git a/src/core/thread/network_diagnostic.hpp b/src/core/thread/network_diagnostic.hpp
index 16b737b67..544f783c2 100644
--- a/src/core/thread/network_diagnostic.hpp
+++ b/src/core/thread/network_diagnostic.hpp
@@ -281,6 +281,7 @@ public:
     uint16_t GetLastQueryId(void) const { return mQueryId; }
 
 private:
+    typedef otNetworkDiagData        DiagData;
     typedef otNetworkDiagIp6AddrList Ip6AddrList;
     typedef otNetworkDiagMacCounters MacCounters;
 
@@ -302,6 +303,7 @@ private:
 
     template <Uri kUri> void HandleTmf(Coap::Msg &aMsg);
 
+    static void ReadDiagData(DiagData &aDiagData, const Message &aMessage, const Tlv::Info &aTlvInfo);
     static void ParseIp6AddrList(Ip6AddrList &aIp6Addrs, const Message &aMessage, OffsetRange aOffsetRange);
     static void ParseMacCounters(const MacCountersTlv &aMacCountersTlv, MacCounters &aMacCounters);
 
diff --git a/src/core/thread/network_diagnostic_tlvs.hpp b/src/core/thread/network_diagnostic_tlvs.hpp
index 3a31382d8..3f7dfdb6a 100644
--- a/src/core/thread/network_diagnostic_tlvs.hpp
+++ b/src/core/thread/network_diagnostic_tlvs.hpp
@@ -591,43 +591,9 @@ private:
 } OT_TOOL_PACKED_END;
 
 /**
- * Implements Channel Pages TLV generation and parsing.
+ * Defines Channel Pages TLV constants and types.
  */
-OT_TOOL_PACKED_BEGIN
-class ChannelPagesTlv : public Tlv, public TlvInfo<Tlv::kChannelPages>
-{
-public:
-    /**
-     * Initializes the TLV.
-     */
-    void Init(void)
-    {
-        SetType(kChannelPages);
-        SetLength(sizeof(*this) - sizeof(Tlv));
-    }
-
-    /**
-     * Indicates whether or not the TLV appears to be well-formed.
-     *
-     * @retval TRUE   If the TLV appears to be well-formed.
-     * @retval FALSE  If the TLV does not appear to be well-formed.
-     */
-    bool IsValid(void) const
-    {
-        // At least one channel page must be included.
-        return GetLength() >= 1;
-    }
-
-    /**
-     * Returns a pointer to the list of Channel Pages.
-     *
-     * @returns A pointer to the list of Channel Pages.
-     */
-    uint8_t *GetChannelPages(void) { return mChannelPages; }
-
-private:
-    uint8_t mChannelPages[Radio::kNumChannelPages];
-} OT_TOOL_PACKED_END;
+typedef TlvInfo<Tlv::kChannelPages> ChannelPagesTlv;
 
 /**
  * Defines Type List TLV constants and types.