diff --git a/pkg/dockerfile/buildargs.go b/pkg/dockerfile/buildargs.go
index bc393f31f..981357e1c 100644
--- a/pkg/dockerfile/buildargs.go
+++ b/pkg/dockerfile/buildargs.go
@@ -33,7 +33,7 @@ func NewBuildArgs(args []string) *BuildArgs {
 		if len(s) == 1 {
 			argsFromOptions[s[0]] = nil
 		} else {
-			argsFromOptions[s[0]] = &s[1]
+			argsFromOptions[s[0]] = &strings.Join(s[1:], "=")
 		}
 	}
 	return &BuildArgs{