She confirmed a meeting took place last Friday with all Councillors to discuss the breach of confidentiality.
"It's our duty as elected representatives to be open and transparent so the district's affairs are run in the best interests of our community."
Extraordinary meetings of Council are called to deal with specific issues, as and when required.
Public notification of the meeting must be given as is reasonable and must include the general nature of the business to be transacted. Legally, either three working days' or 24 hours' notice must be given.
Former Hastings Mayor, Lawrence Yule, who served from 2001 to 2017, said it wasn't "unheard of", but relatively rare.
From February 1, 2012, 15 extraordinary meetings have been held, including Friday's scheduled meeting. Five, in Hazlehurst's term as mayor.
Yule recalls about one or two held each year.
"It is a regime that is allowed for but the biggest disadvantage of it is that it doesn't give that much notice for papers to be delivered and people to read material."
In his time, he says they were generally done when things needed "urgent consideration or they couldn't wait". He noted the upcoming election could be why the meeting has been called so soon.
"When I was mayor, I didn't like calling them unless I had to but we did call them every now and again."