diff --git a/src/core/coap/coap.cpp b/src/core/coap/coap.cpp
index d2136ea03..c02d63b3b 100644
--- a/src/core/coap/coap.cpp
+++ b/src/core/coap/coap.cpp
@@ -49,10 +49,10 @@
 namespace ot {
 namespace Coap {
 
-Coap::Coap(ThreadNetif &aNetif):
+Coap::Coap(ThreadNetif &aNetif, Timer::Handler aRetransmissionHandler):
     ThreadNetifLocator(aNetif),
     mSocket(aNetif.GetIp6().mUdp),
-    mRetransmissionTimer(aNetif.GetInstance(), &Coap::HandleRetransmissionTimer, this),
+    mRetransmissionTimer(aNetif.GetInstance(), aRetransmissionHandler, this),
     mResources(NULL),
     mContext(NULL),
     mInterceptor(NULL),
diff --git a/src/core/coap/coap.hpp b/src/core/coap/coap.hpp
index 05637c261..442aac11c 100644
--- a/src/core/coap/coap.hpp
+++ b/src/core/coap/coap.hpp
@@ -443,10 +443,11 @@ public:
     /**
      * This constructor initializes the object.
      *
-     * @param[in]  aNetif    A reference to the Netif object.
+     * @param[in]  aNetif                   A reference to the Netif object.
+     * @param[in]  aRetransmissionHandler   An optional pointer to the retransmission handler, used by CoapSecure.
      *
      */
-    Coap(ThreadNetif &aNetif);
+    Coap(ThreadNetif &aNetif, Timer::Handler aRetransmissionHandler = &Coap::HandleRetransmissionTimer);
 
     /**
      * This method starts the CoAP service.
@@ -646,6 +647,12 @@ public:
     const MessageQueue &GetCachedResponses(void) const { return mResponsesQueue.GetResponses(); }
 
 protected:
+    /**
+     * Retransmission timer handler.
+     *
+     */
+    void HandleRetransmissionTimer(void);
+
     /**
      * This method send a message.
      *
@@ -688,8 +695,8 @@ private:
     otError SendCopy(const Message &aMessage, const Ip6::MessageInfo &aMessageInfo);
     otError SendEmptyMessage(Header::Type aType, const Header &aRequestHeader,
                              const Ip6::MessageInfo &aMessageInfo);
+
     static void HandleRetransmissionTimer(Timer &aTimer);
-    void HandleRetransmissionTimer(void);
 
     static Coap &GetOwner(const Context &aContext);
 
diff --git a/src/core/coap/coap_secure.cpp b/src/core/coap/coap_secure.cpp
index 25f5117a8..379b2d8cc 100644
--- a/src/core/coap/coap_secure.cpp
+++ b/src/core/coap/coap_secure.cpp
@@ -48,7 +48,7 @@ namespace ot {
 namespace Coap {
 
 CoapSecure::CoapSecure(ThreadNetif &aNetif):
-    Coap(aNetif),
+    Coap(aNetif, &CoapSecure::HandleRetransmissionTimer),
     mConnectedCallback(NULL),
     mConnectedContext(NULL),
     mTransportCallback(NULL),
@@ -320,6 +320,11 @@ CoapSecure &CoapSecure::GetOwner(const Context &aContext)
     return coap;
 }
 
+void CoapSecure::HandleRetransmissionTimer(Timer &aTimer)
+{
+    GetOwner(aTimer).Coap::HandleRetransmissionTimer();
+}
+
 }  // namespace Coap
 }  // namespace ot
 
diff --git a/src/core/coap/coap_secure.hpp b/src/core/coap/coap_secure.hpp
index 8ef72ea8d..6a98ac36e 100644
--- a/src/core/coap/coap_secure.hpp
+++ b/src/core/coap/coap_secure.hpp
@@ -214,6 +214,8 @@ private:
     static void HandleUdpTransmit(Tasklet &aTasklet);
     void HandleUdpTransmit(void);
 
+    static void HandleRetransmissionTimer(Timer &aTimer);
+
     static CoapSecure &GetOwner(const Context &aContext);
 
     Ip6::MessageInfo mPeerAddress;