diff --git a/src/devices/nm-device-wifi.c b/src/devices/nm-device-wifi.c
index e91214e16..6b47225fb 100644
--- a/src/devices/nm-device-wifi.c
+++ b/src/devices/nm-device-wifi.c
@@ -1438,7 +1438,7 @@ impl_device_request_scan (NMDeviceWifi *self,
 {
 	NMDeviceWifiPrivate *priv = NM_DEVICE_WIFI_GET_PRIVATE (self);
 	NMDevice *device = NM_DEVICE (self);
-	time_t last_scan;
+	gint32 last_scan;
 	GError *error;
 
 	if (   !priv->enabled
@@ -1459,7 +1459,7 @@ impl_device_request_scan (NMDeviceWifi *self,
 	}
 
 	last_scan = nm_supplicant_interface_get_last_scan_time (priv->supplicant.iface);
-	if ((time (NULL) - last_scan) < 10) {
+	if (last_scan && (nm_utils_get_monotonic_timestamp_s () - last_scan) < 10) {
 		error = g_error_new_literal (NM_WIFI_ERROR,
 		                             NM_WIFI_ERROR_SCAN_NOT_ALLOWED,
 		                             "Scanning not allowed immediately following previous scan");
diff --git a/src/supplicant-manager/nm-supplicant-interface.c b/src/supplicant-manager/nm-supplicant-interface.c
index 4063085c3..789039c7a 100644
--- a/src/supplicant-manager/nm-supplicant-interface.c
+++ b/src/supplicant-manager/nm-supplicant-interface.c
@@ -24,6 +24,7 @@
 #include <string.h>
 #include <glib.h>
 
+#include "NetworkManagerUtils.h"
 #include "nm-supplicant-interface.h"
 #include "nm-supplicant-manager.h"
 #include "nm-logging.h"
@@ -106,7 +107,7 @@ typedef struct {
 	guint32               blobs_left;
 	GHashTable *          bss_proxies;
 
-	time_t                last_scan;
+	gint32                last_scan; /* timestamp as returned by nm_utils_get_monotonic_timestamp_s() */
 
 	NMSupplicantConfig *  cfg;
 
@@ -167,7 +168,7 @@ bss_properties_changed (DBusGProxy *proxy,
 	NMSupplicantInterfacePrivate *priv = NM_SUPPLICANT_INTERFACE_GET_PRIVATE (self);
 
 	if (priv->scanning)
-		priv->last_scan = time (NULL);
+		priv->last_scan = nm_utils_get_monotonic_timestamp_s ();
 
 	if (g_strcmp0 (interface, WPAS_DBUS_IFACE_BSS) == 0)
 		g_signal_emit (self, signals[BSS_UPDATED], 0, dbus_g_proxy_get_path (proxy), props);
@@ -230,7 +231,7 @@ wpas_iface_bss_added (DBusGProxy *proxy,
 	NMSupplicantInterfacePrivate *priv = NM_SUPPLICANT_INTERFACE_GET_PRIVATE (self);
 
 	if (priv->scanning)
-		priv->last_scan = time (NULL);
+		priv->last_scan = nm_utils_get_monotonic_timestamp_s ();
 
 	handle_new_bss (self, object_path, props);
 }
@@ -334,7 +335,7 @@ set_state (NMSupplicantInterface *self, guint32 new_state)
 
 	if (   priv->state == NM_SUPPLICANT_INTERFACE_STATE_SCANNING
 	    || old_state == NM_SUPPLICANT_INTERFACE_STATE_SCANNING)
-		priv->last_scan = time (NULL);
+		priv->last_scan = nm_utils_get_monotonic_timestamp_s ();
 
 	/* Disconnect reason is no longer relevant when not in the DISCONNECTED state */
 	if (priv->state != NM_SUPPLICANT_INTERFACE_STATE_DISCONNECTED)
@@ -367,7 +368,7 @@ set_scanning (NMSupplicantInterface *self, gboolean new_scanning)
 
 		/* Cache time of last scan completion */
 		if (priv->scanning == FALSE)
-			priv->last_scan = time (NULL);
+			priv->last_scan = nm_utils_get_monotonic_timestamp_s ();
 
 		g_object_notify (G_OBJECT (self), "scanning");
 	}
@@ -388,7 +389,7 @@ nm_supplicant_interface_get_scanning (NMSupplicantInterface *self)
 	return FALSE;
 }
 
-time_t
+gint32
 nm_supplicant_interface_get_last_scan_time (NMSupplicantInterface *self)
 {
 	return NM_SUPPLICANT_INTERFACE_GET_PRIVATE (self)->last_scan;
@@ -403,7 +404,7 @@ wpas_iface_scan_done (DBusGProxy *proxy,
 	NMSupplicantInterfacePrivate *priv = NM_SUPPLICANT_INTERFACE_GET_PRIVATE (self);
 
 	/* Cache last scan completed time */
-	priv->last_scan = time (NULL);
+	priv->last_scan = nm_utils_get_monotonic_timestamp_s ();
 	g_signal_emit (self, signals[SCAN_DONE], 0, success);
 }
 
diff --git a/src/supplicant-manager/nm-supplicant-interface.h b/src/supplicant-manager/nm-supplicant-interface.h
index 2f0233cf7..633c16cc5 100644
--- a/src/supplicant-manager/nm-supplicant-interface.h
+++ b/src/supplicant-manager/nm-supplicant-interface.h
@@ -144,7 +144,7 @@ const char *nm_supplicant_interface_state_to_string (guint32 state);
 
 gboolean nm_supplicant_interface_get_scanning (NMSupplicantInterface *self);
 
-time_t nm_supplicant_interface_get_last_scan_time (NMSupplicantInterface *self);
+gint32 nm_supplicant_interface_get_last_scan_time (NMSupplicantInterface *self);
 
 const char *nm_supplicant_interface_get_ifname (NMSupplicantInterface *self);