Auckland Transport is urging HOP cardholders using a popular smartphone app to change their passwords after another bug struck the travel card.
The council body became aware of the problem when some credit card top-ups to AT HOP card accounts began stalling on the Kiwi Hub app.
The issue follows a bug that froze money on HOP cards for about 16,000 users. It led to balances disappearing if people topped the their card online and did not tag on within 60 days. That bug has now been fixed.
An AT spokesman said last month it noticed some credit card top-ups to AT HOP accounts were beginning to stall.
The top-ups were stalling meaning money wasn't going out of accounts - there was no security breach and no unauthorised transfers, he said.