diff --git a/src/rez/cli/pkg-cache.py b/src/rez/cli/pkg-cache.py
index 367b7a0af..c35f27ecc 100644
--- a/src/rez/cli/pkg-cache.py
+++ b/src/rez/cli/pkg-cache.py
@@ -41,6 +41,14 @@ def setup_parser(parser, completions=False):
     group.add_argument(
         "--daemon", action="store_true", help=SUPPRESS
     )
+    parser.add_argument(
+        "--pkg-cache-mode",
+        choices=["sync", "async"],
+        default=None,
+        help="If provided, override the rezconfig's package_cache_async key. "
+             "If 'sync', the process will block until packages are cached. "
+             "If 'async', the process will not block while packages are cached."
+    )
     parser.add_argument(
         "-c", "--columns", nargs='+', choices=column_choices,
         default=["status", "package", "variant_uri", "cache_path"],
@@ -59,6 +67,7 @@ def setup_parser(parser, completions=False):
 
 
 def add_variant(pkgcache, uri, opts):
+    from rez.config import config
     from rez.packages import get_variant_from_uri
     from rez.utils.logging_ import print_info, print_warning
     from rez.package_cache import PackageCache
@@ -70,7 +79,17 @@ def add_variant(pkgcache, uri, opts):
         print("No such variant: %s" % uri, file=sys.stderr)
         sys.exit(1)
 
-    destpath, status = pkgcache.add_variant(variant, force=opts.force)
+    if opts.pkg_cache_mode == "async":
+        sync = False
+    elif opts.pkg_cache_mode == "sync":
+        sync = True
+    else:
+        sync = not config.package_cache_async
+
+    destpath, status = pkgcache.add_variant(
+        variant, force=opts.force,
+        wait_for_copying=sync
+    )
 
     if status == PackageCache.VARIANT_FOUND:
         print_info("Already exists: %s", destpath)