diff --git a/installer/data/mysql/atomicupdate/bug_34000.pl b/installer/data/mysql/atomicupdate/bug_34000.pl
new file mode 100755
index 0000000000..07eec95787
--- /dev/null
+++ b/installer/data/mysql/atomicupdate/bug_34000.pl
@@ -0,0 +1,48 @@
+use Modern::Perl;
+use Koha::Installer::Output qw(say_warning say_success say_info);
+
+return {
+    bug_number  => "34000",
+    description => "Prevent re-issuance of auto-generated cardnumbers",
+    up          => sub {
+        my ($args) = @_;
+        my ( $dbh, $out ) = @$args{qw(dbh out)};
+
+        my $exists = $dbh->selectrow_array(q{SELECT 1 FROM systempreferences WHERE variable = 'autoMemberNumValue'});
+
+        if ($exists) {
+            say_warning( $out, "System preference 'autoMemberNumValue' already exists, skipping" );
+            return;
+        }
+
+        # Seed from the highest numeric cardnumber ever issued, considering both live
+        # and deleted patrons so pre-upgrade deletions don't free up their numbers.
+        my ($seed) = $dbh->selectrow_array(
+            q{
+            SELECT COALESCE(
+                GREATEST(
+                    COALESCE(
+                        (SELECT MAX(CAST(cardnumber AS SIGNED)) FROM borrowers
+                          WHERE cardnumber REGEXP '^-?[0-9]+$'),
+                        0
+                    ),
+                    COALESCE(
+                        (SELECT MAX(CAST(cardnumber AS SIGNED)) FROM deletedborrowers
+                          WHERE cardnumber REGEXP '^-?[0-9]+$'),
+                        0
+                    )
+                ),
+                0
+            )
+        }
+        );
+        $seed //= 0;
+
+        $dbh->do(
+            q{INSERT IGNORE INTO systempreferences (variable, value) VALUES ('autoMemberNumValue', ?)},
+            undef, $seed
+        );
+
+        say_success( $out, "Added new system preference 'autoMemberNumValue' seeded to $seed" );
+    },
+};
diff --git a/installer/data/mysql/mandatory/sysprefs.sql b/installer/data/mysql/mandatory/sysprefs.sql
index c442345d39..f295a3b39c 100644
--- a/installer/data/mysql/mandatory/sysprefs.sql
+++ b/installer/data/mysql/mandatory/sysprefs.sql
@@ -101,6 +101,7 @@ INSERT INTO systempreferences ( `variable`, `value`, `options`, `explanation`, `
 ('AutomaticEmailReceipts','0',NULL,'Send email receipts for payments and write-offs','YesNo'),
 ('AutomaticItemReturn','1',NULL,'If ON, Koha will automatically set up a transfer of this item to its homebranch','YesNo'),
 ('autoMemberNum','0',NULL,'If ON, patron number is auto-calculated','YesNo'),
+('autoMemberNumValue','0',NULL,'Stores the last auto-generated cardnumber to prevent re-issuance','Integer'),
 ('AutoRemoveOverduesRestrictions','no','no|when_no_overdue|when_no_overdue_causing_debarment', 'Defines if and on what conditions OVERDUES debarments should automatically be lifted when overdue items are returned by the patron.','Choice'),
 ('AutoRenewalNotices','preferences','cron|preferences|never','How should Koha determine whether to end autorenewal notices','Choice'),
 ('AutoResumeSuspendedHolds','1',NULL,'Allow suspended holds to be automatically resumed by a set date.','YesNo'),