diff --git a/cmd/krel/cmd/obs_stage.go b/cmd/krel/cmd/obs_stage.go
index 33c23d473c2..3f2010fea19 100644
--- a/cmd/krel/cmd/obs_stage.go
+++ b/cmd/krel/cmd/obs_stage.go
@@ -23,6 +23,7 @@ import (
 	"github.com/sirupsen/logrus"
 	"github.com/spf13/cobra"
 
+	"k8s.io/release/pkg/gcp/gcb"
 	"k8s.io/release/pkg/obs"
 	"k8s.io/release/pkg/release"
 )
@@ -115,7 +116,7 @@ func init() {
 		)
 
 	obsStageCmd.PersistentFlags().
-		StringArrayVar(
+		StringSliceVar(
 			&obsStageOptions.Packages,
 			obsPackagesFlag,
 			obsStageOptions.Packages,
@@ -123,7 +124,7 @@ func init() {
 		)
 
 	obsStageCmd.PersistentFlags().
-		StringArrayVar(
+		StringSliceVar(
 			&obsStageOptions.Architectures,
 			obsArchitecturesFlag,
 			obsStageOptions.Architectures,
@@ -181,6 +182,23 @@ func init() {
 
 func runOBSStage(options *obs.StageOptions) error {
 	options.NoMock = rootOpts.nomock
+
+	// Allow submitting packages and architectures separated by the string
+	// slice separator. This allows us to pass the GCB substitution, which
+	// already uses comma as default separator.
+	// We cannot use the GCB separator substitution (see `gcloud topic
+	// escaping`) because GCB complains that a 'build tag must match format
+	// "^[\\w][\\w.-]{0,127}$"'.
+	archSplit := strings.Split(options.Architectures[0], gcb.StringSliceSeparator)
+	if len(archSplit) > 1 {
+		options.Architectures = archSplit
+	}
+
+	packageSplit := strings.Split(options.Packages[0], gcb.StringSliceSeparator)
+	if len(packageSplit) > 1 {
+		options.Packages = packageSplit
+	}
+
 	stage := obs.NewStage(options)
 	if submitJob {
 		// Perform a local check of the specified options before launching a
diff --git a/gcb/obs-stage/cloudbuild.yaml b/gcb/obs-stage/cloudbuild.yaml
index 4146e4a83f4..7dc4f40112e 100644
--- a/gcb/obs-stage/cloudbuild.yaml
+++ b/gcb/obs-stage/cloudbuild.yaml
@@ -82,8 +82,7 @@ steps:
   - "--log-level=${_LOG_LEVEL}"
   - "--template-dir=${_SPEC_TEMPLATE_PATH}"
   - "--packages=${_PACKAGES}"
-  # TODO(xmudrii) - followup: solve problem with delimiter
-  # - "--architectures=${_ARCHITECTURES}"
+  - "--architectures=${_ARCHITECTURES}"
   - "--version=${_VERSION}"
   - "--project=${_OBS_PROJECT}"
   - "--source=${_PACKAGE_SOURCE}"
@@ -97,6 +96,7 @@ tags:
 - ${_TYPE_TAG}
 - ${_TYPE}
 - ${_PACKAGES}
+- ${_ARCHITECTURES}
 - ${_VERSION}
 - ${_OBS_PROJECT_TAG}
 
diff --git a/pkg/gcp/gcb/gcb.go b/pkg/gcp/gcb/gcb.go
index 6722d7ee900..f9e62464026 100644
--- a/pkg/gcp/gcb/gcb.go
+++ b/pkg/gcp/gcb/gcb.go
@@ -42,6 +42,10 @@ import (
 	"sigs.k8s.io/release-utils/util"
 )
 
+// StringSliceSeparator is the separator used for passing string slices as GCB
+// substitutions.
+const StringSliceSeparator = "..."
+
 // GCB is the main structure of this package.
 type GCB struct {
 	options        *Options
@@ -391,9 +395,8 @@ func (g *GCB) SetGCBSubstitutions(toolOrg, toolRepo, toolRef, gcsBucket string)
 	switch {
 	case g.options.OBSStage:
 		gcbSubs["SPEC_TEMPLATE_PATH"] = g.options.SpecTemplatePath
-		gcbSubs["PACKAGES"] = strings.Join(g.options.Packages, ",")
-		//nolint:gocritic // This needs some fixes that will be done in a follow-up
-		// gcbSubs["ARCHITECTURES"] = strings.Join(g.options.Architectures, ",")
+		gcbSubs["PACKAGES"] = strings.Join(g.options.Packages, StringSliceSeparator)
+		gcbSubs["ARCHITECTURES"] = strings.Join(g.options.Architectures, StringSliceSeparator)
 		gcbSubs["VERSION"] = g.options.Version
 		gcbSubs["OBS_PROJECT"] = g.options.OBSProject
 		gcbSubs["OBS_PROJECT_TAG"] = strings.ReplaceAll(g.options.OBSProject, ":", "-")
@@ -402,7 +405,7 @@ func (g *GCB) SetGCBSubstitutions(toolOrg, toolRepo, toolRef, gcsBucket string)
 		// Stop here when doing OBS stage
 		return gcbSubs, nil
 	case g.options.OBSRelease:
-		gcbSubs["PACKAGES"] = strings.Join(g.options.Packages, ",")
+		gcbSubs["PACKAGES"] = strings.Join(g.options.Packages, StringSliceSeparator)
 		gcbSubs["OBS_PROJECT"] = g.options.OBSProject
 		gcbSubs["OBS_PROJECT_TAG"] = strings.ReplaceAll(g.options.OBSProject, ":", "-")