Dungog's new flood plan doesn't outline the flash flood trigger points for the creek that caused a major inundation during the 2015 superstorm, a court has heard.
But the State Emergency Service says it will work with Dungog Shire Council to update the plan, which went on public exhibition earlier this year.
SES Hunter Region controller Stephen Hart gave evidence on the fourth day of the inquest into the deaths of Colin Webb, 79, Robin Macdonald, 68, and Brian Wilson, 72, at Newcastle courthouse on Thursday.
The trio died during a flood on the morning of April 21.
The court heard that the flash flood started at 5.05am after Myall Creek backed up.
The Williams River did not peak until after the flash flood.
But the court heard that the new Dungog flood plan principally dealt with triggers – or causes – behind river flooding.
The plan makes several references to Myall Creek and points out that it can flood independently of the Williams River.
However, the court heard the plan doesn’t include information about the creek’s trigger points.
Mr Hart said the SES was preparing a flash flood action card for the Myall Creek and would work with council to update the 2017 flood plan.
The inquest, before Deputy State Coroner Teresa O'Sullivan, continues.