diff --git a/NAMESPACE b/NAMESPACE
index faa6e0b0ef3b8fb622a221d527314ed7c24c392e..f1227efb4692178842e9f99eda40b3125eff8319 100644
--- a/NAMESPACE
+++ b/NAMESPACE
@@ -52,6 +52,7 @@ export(getSD_Ids)
 export(isNodeDownstream)
 export(isNodeUpstream)
 export(plot.Qm3s)
+export(plot.mermaid)
 export(reduceGRiwrm)
 export(transferGRparams)
 import(airGR)
diff --git a/R/plot.GRiwrm.R b/R/plot.GRiwrm.R
index dac56b09aef10f827c8c526aee1605dabc3c2420..a3a28009422fa371c30a8751489a48005641948e 100644
--- a/R/plot.GRiwrm.R
+++ b/R/plot.GRiwrm.R
@@ -221,6 +221,7 @@ plot_png = function(path, add=FALSE)
 #' @param ... Not used
 #'
 #' @return Nothing, used for side effect.
+#' @export plot.mermaid
 #' @export
 #'
 #' @examples