diff --git a/rust/htp/src/request.rs b/rust/htp/src/request.rs
index b132e0762f..faa1a8e452 100644
--- a/rust/htp/src/request.rs
+++ b/rust/htp/src/request.rs
@@ -400,10 +400,14 @@ impl ConnectionParser {
                 let (len, ext) = parse_chunked_length(&data2)?;
                 self.request_chunked_length = len;
                 if ext {
-                    htp_warn!(
+                    let mut flags = 0; // unused but needed by macro
+                    htp_warn_once!(
                         self.logger,
                         HtpLogCode::REQUEST_CHUNK_EXTENSION,
-                        "Request chunk extension"
+                        "Request chunk extension",
+                        self.request_mut().unwrap().flags,
+                        flags,
+                        HtpFlags::FIELD_REQ_CHUNK_EXTENSION
                     );
                 }
                 let len = len.as_ref().ok_or(HtpStatus::ERROR).map_err(|e| {
diff --git a/rust/htp/src/response.rs b/rust/htp/src/response.rs
index 2a3038c97e..1bcc20a221 100644
--- a/rust/htp/src/response.rs
+++ b/rust/htp/src/response.rs
@@ -222,10 +222,14 @@ impl ConnectionParser {
                         Ok((len, ext)) => {
                             self.response_chunked_length = len;
                             if ext {
-                                htp_warn!(
+                                let mut flags = 0; // unused but needed by macro
+                                htp_warn_once!(
                                     self.logger,
                                     HtpLogCode::RESPONSE_CHUNK_EXTENSION,
-                                    "Response chunk extension"
+                                    "Response chunk extension",
+                                    self.response_mut().unwrap().flags,
+                                    flags,
+                                    HtpFlags::FIELD_RESP_CHUNK_EXTENSION
                                 );
                             }
                             // Handle chunk length
diff --git a/rust/htp/src/util.rs b/rust/htp/src/util.rs
index ff38dfbe7b..dda40cb745 100644
--- a/rust/htp/src/util.rs
+++ b/rust/htp/src/util.rs
@@ -143,6 +143,10 @@ impl HtpFlags {
     pub const HEADERS_TOO_MANY: u64 = 0x0040_0000_0000;
     /// 100-Continue already seen.
     pub const FIELD_100_CONTINUE: u64 = 0x0080_0000_0000;
+    /// Request chunk extension, log only once.
+    pub const FIELD_REQ_CHUNK_EXTENSION: u64 = 0x0100_0000_0000;
+    /// Response chunk extension, log only once.
+    pub const FIELD_RESP_CHUNK_EXTENSION: u64 = 0x0200_0000_0000;
 }
 
 #[allow(clippy::upper_case_acronyms)]