A claim by junior doctors that they're being gagged is misleading, district health boards (DHBs) say.
Junior doctors have rejected a new pay offer from the health boards and will begin their second 48-hour strike on 23 November.
The junior doctors' union said the board has threatened disciplinary action against doctors who spoke publicly without their employer's consent.
In response, the DHBs have released a copy of their letter to the union.
It said they acknowledged doctors' rights to speak out, but policies require employees not to make comments or statements without consent.
It said by identifying themselves as employees of particular boards or hospitals, doctors could face disciplinary action.
The letter asked the union to ensure the doctors do not identify themselves as working for any specific health board, but as union members.