The Betsi Cadwaladr health board in north Wales is to remain under the highest level of Welsh Government supervision.
In a written statement, Health Minister Vaughan Gething said the health board would stay in "special measures".
He said the board had made progress but concerns remained "on performance and strategic solutions".
"Further assurance" was needed on mental health services, he added.
Betsi Cadwaladr has been in special measures since 2015 after "institutional abuse" was found at a mental health unit.
The Welsh Government, to tackle serious problems in the NHS, places health boards under increased levels of supervision.
There are four levels for health boards to operate at: routine arrangements, enhanced monitoring, targeted intervention and special measures.
Two other boards, Hywel Dda and Swansea Bay, have had their status improved from targeted intervention to enhanced monitoring.
The Aneurin Bevan, Cardiff and Vale, Powys boards, and Velindre as well as the Welsh Ambulance Service trusts are all on routine arrangements.
Maternity services at the Cwm Taf Morgannwg remain in special measures.
Plaid Cymru health spokesman Rhun ap Iorwerth said the news confirmed his belief that Betsi Cadwaladr health board "has to go".
"A fresh start is needed, for staff and patients across north Wales," he said.