diff --git a/src/library/base/man/connections.Rd b/src/library/base/man/connections.Rd
index 6b5699e6bc..538c679d0f 100644
--- a/src/library/base/man/connections.Rd
+++ b/src/library/base/man/connections.Rd
@@ -120,10 +120,10 @@ socketTimeout(socket, timeout = -1)
     requests.  It is ignored for non-HTTP URLs.  The \code{User-Agent}
     header, coming from the \code{HTTPUserAgent} option (see
     \code{\link{options}}) is used as the first header, automatically.}
-  \item{compression}{integer in 0--9.  The amount of compression to be
-    applied when writing, from none to maximal available.  For
-    \code{xzfile} and \code{zstdfile} can also be negative: see the
-    \sQuote{Compression} section.}
+  \item{compression}{integer in 0--9 (1--19 for \code{zsdfile}).  The
+    amount of compression to be applied when writing, from minimal to
+    maximal available.  For \code{xzfile} and \code{zstdfile} can also
+    be negative: see the \sQuote{Compression} section.}
   \item{timeout}{numeric: the timeout (in seconds) to be used for this
     connection.  Beware that some OSes may treat very large values as
     zero: however the POSIX standard requires values up to 31 days to be
diff --git a/src/main/connections.c b/src/main/connections.c
index e711a2b933..6b87d38bda 100644
--- a/src/main/connections.c
+++ b/src/main/connections.c
@@ -2754,11 +2754,16 @@ attribute_hidden SEXP do_gzfile(SEXP call, SEXP op, SEXP args, SEXP env)
 	if(compress == NA_LOGICAL || compress < 0 || compress > 9)
 	    error(_("invalid '%s' argument"), "compress");
     }
-    if(type == 2 || type == 3) {
+    if(type == 2) {
 	compress = asInteger(CADDDR(args));
 	if(compress == NA_LOGICAL || abs(compress) > 9)
 	    error(_("invalid '%s' argument"), "compress");
     }
+    if(type == 3) {
+	compress = asInteger(CADDDR(args));
+	if(compress == NA_LOGICAL || abs(compress) > 19)
+	    error(_("invalid '%s' argument"), "compress");
+    }
     open = CHAR(STRING_ELT(sopen, 0)); /* ASCII */
     if (type == 0 && (!open[0] || open[0] == 'r')) {
 	/* check magic no */