diff --git a/tests/sys/net/routing/test_routing_l3.py b/tests/sys/net/routing/test_routing_l3.py
--- a/tests/sys/net/routing/test_routing_l3.py
+++ b/tests/sys/net/routing/test_routing_l3.py
@@ -86,6 +86,47 @@
         nh = [nh for nh in nhops if nh["index"] == nhop_kidx][0]
         assert nh["ifa"] == str(second_addr.ip)
 
+    @pytest.mark.parametrize("family", ["inet", "inet6"])
+    @pytest.mark.require_user("root")
+    def test_add_address_same_prefix_present(self, family):
+        """
+        Tests adding an interface prefix route when a route with the same
+        prefix is already present in the routing table
+        """
+        vnet = self.vnet_map["vnet1"]
+        first_iface = vnet.iface_alias_map["if1"]
+
+        if family == "inet":
+            first_addr = ipaddress.ip_interface("192.0.2.1/24")
+        else:
+            first_addr = ipaddress.ip_interface("2001:db8::1/64")
+
+        # Add a route pointing to the loopback interface
+        ToolsHelper.print_output(
+            f"route add -net -{family} {first_addr.network} -interface lo0"
+        )
+
+        # Verify the route points to the loopback interface
+        routes = ToolsHelper.get_routes(family)
+        px = [
+            r for r in routes if r["destination"] == str(first_addr.network)
+        ][0]
+        assert px["interface-name"] == "lo0"
+
+        # Add an address to the first interface with the same prefix as the
+        # route, and verify switchover
+        first_iface.setup_addr(str(first_addr))
+
+        routes = ToolsHelper.get_routes(family)
+        px = [
+            r for r in routes if r["destination"] == str(first_addr.network)
+        ][0]
+        nhop_kidx = px["nhop"]
+        assert px["interface-name"] == first_iface.name
+        nhops = ToolsHelper.get_nhops(family)
+        nh = [nh for nh in nhops if nh["index"] == nhop_kidx][0]
+        assert nh["ifa"] == str(first_addr.ip)
+
 
 class TestRouteCornerCase1(SingleVnetTestTemplate):
     @pytest.mark.parametrize("family", ["inet", "inet6"])