Hadley said yesterday the council earlier this year asked deputy mayor Nobby Clark to assume some mayoral duties in light of ''the unique circumstances'' at the council.
The need to use electronic access and to share information about the mayor's activities was discussed in order to support that work, she said.
''It is common for council staff to assist the mayor, elected members and executive staff with administration to ensure timely response to emails. This does not include monitoring.
''Although these arrangements were agreed, I should not have shared the contents of an email the mayor issued to media last week.
''A review of arrangements will be undertaken.''
Sir Tim did not recall signing or agreeing to any such arrangements.
''To me the whole issue is the lack of consent.''
His deputy, Cr Clark, intends to ensure there is an appropriate investigation on the matter of the email.
It would include advice from a number of external and independent advisers, he said.
''Once this investigation is completed, I will be able to release the outcomes, including our pathway forward, regarding the issues raised.''
Employment lawyer Susan Hornsby-Geluk said the council might have broken the law by accessing Sir Tim's emails as he was not an employee.
If he was, his employers would be entitled to monitor his emails and to make whatever checks they might think necessary, but in this case it was a bit different as he was an elected member, she said.
''There are potentially Privacy Act issues that arise out of that because there is not necessarily an inherent right on the part of the organisation to be reviewing emails.''
''The chief executive does not employ the mayor, he is an elected representative and is not accountable in that aspect to the chief executive.''
She would find it surprising if the chief executive had the power to go through his emails, but in the end, it would come down to the basis upon Hadley acted which could include a specific policy or an agreement.
''If there was no legitimate basis, it was potentially a breach of [the] Privacy Act.''
Auckland University Associate Prof Gehan Nilendra Gunasekara who was an expert in privacy law described the situation as a grey area.
''There is no black and white rule that a chief executive could never access the mayor's email because she might have a very valid reasons for why the mayor should be treated no different than any other employee. It could be a blackmail going on, it could be a security threat — there are a whole range of reasons.
''My ... advice to anyone [who] sends an email should assume their email is not private.''
Local government expert, former Massey University lecturer Dr Andy Asquith believed it was
inappropriate for any chief executive to read emails from elected members.
''I know situations which employers can read emails from their employees but, in this case, the chief executive is their employee.
''The act of reading [his] email is indefensible.''
Meanwhile, a six-month review of the council's progress addressing the issues highlighted in the Thomson Report are due to be released later this week.
The report, which was released last year, highlighted issues within council including Sir Tim's struggle to fulfil significant aspects of his job, the relationship between the mayor and the council chief executive, and the appointment of Cr Clark as deputy mayor.