diff --git a/ext/intl/msgformat/msgformat_helpers.cpp b/ext/intl/msgformat/msgformat_helpers.cpp
index 430d5a741115f..8149f34c75e82 100644
--- a/ext/intl/msgformat/msgformat_helpers.cpp
+++ b/ext/intl/msgformat/msgformat_helpers.cpp
@@ -448,6 +448,10 @@ U_CFUNC void umsg_format_helper(MessageFormatter_object *mfo,
 					 * as a result of that.
 					 */
 					str = zval_get_tmp_string(elem, &tmp_str);
+					if (!str || !ZSTR_LEN(str)) {
+						EG(exception) = NULL;
+						return;
+					}
 
 					UnicodeString *text = new UnicodeString();
 					intl_stringFromChar(*text,
diff --git a/ext/intl/tests/gh16814.phpt b/ext/intl/tests/gh16814.phpt
new file mode 100644
index 0000000000000..d45c91bf8719c
--- /dev/null
+++ b/ext/intl/tests/gh16814.phpt
@@ -0,0 +1,12 @@
+--TEST--
+GH-16814 (MessageFormatter::format throws error on unused parameter)
+--EXTENSIONS--
+intl
+--FILE--
+<?php
+$fmt = new MessageFormatter('de', 'Beispiel ohne Benutzung');
+$fmt->format(['payed' => new DateTimeImmutable()]);
+echo "OK";
+?>
+--EXPECT--
+OK