diff --git a/docs/report_queries/invalid_xref.md b/docs/report_queries/invalid_xref.md
index e3fca754b..a2ab3c4f5 100644
--- a/docs/report_queries/invalid_xref.md
+++ b/docs/report_queries/invalid_xref.md
@@ -11,7 +11,7 @@ PREFIX rdfs: <http://www.w3.org/2000/01/rdf-schema#>
 SELECT DISTINCT ?entity ?property ?value WHERE {
   VALUES ?property {oboInOwl:hasDbXref}
   ?entity ?property ?value .
-  FILTER (!regex(?value, "^[a-z|A-Z|_|\\-|0-9]*:(?!$)\\S*$"))
+  FILTER (!regex(?value, "^[A-Za-z_][A-Za-z0-9_.-]*[A-Za-z0-9_]:[^\\s]+$"))
   FILTER (!isBlank(?entity))
 }
 ORDER BY ?entity
diff --git a/robot-core/src/main/resources/report_queries/invalid_xref.rq b/robot-core/src/main/resources/report_queries/invalid_xref.rq
index 85b754264..fb6226279 100644
--- a/robot-core/src/main/resources/report_queries/invalid_xref.rq
+++ b/robot-core/src/main/resources/report_queries/invalid_xref.rq
@@ -10,7 +10,7 @@ PREFIX rdfs: <http://www.w3.org/2000/01/rdf-schema#>
 SELECT DISTINCT ?entity ?property ?value WHERE {
   VALUES ?property {oboInOwl:hasDbXref}
   ?entity ?property ?value .
-  FILTER (!regex(?value, "^[a-z|A-Z|_|\\-|0-9]*:(?!$)\\S*$"))
+  FILTER (!regex(?value, "^[A-Za-z_][A-Za-z0-9_.-]*[A-Za-z0-9_]:[^\\s]+$"))
   FILTER (!isBlank(?entity))
 }
 ORDER BY ?entity