Councillors say a review presented at a council committee meeting today showed it was appropriate for chief executive Clare Hadley to access the email and share its contents at a behind-closed doors meeting earlier this year.
But, Sir Tim said he was vindicated by the findings.
He has also asked for a further investigation into the matter as he believed the investigation carried by Robert Buchanan "swept the issue under the carpet".
In August, Sir Tim told a Local Democracy Reporter he believed Mrs Hadley had accessed one of his emails and used it against him at a chair’s meeting.
Mrs Hadley later issued a statement acknowledging she should have not shared the contents of the email with other elected members and staff.
However, she highlighted, that on April 27, the council passed a resolution authorising her to take the necessary steps to assist deputy mayor Nobby Clark in his support of the mayor and to represent the city.
Following coverage of the intercepted email the council approved a budget of $10,000 to undertake a review of the arrangements in place for electronic access to the mayor’s email account.
In it, Mr Buchanan said the arrangements in place were lawful, but could not reach a conclusion if the email in question could be considered a personal communication, as the system in place did not extend to purposes of media management.
"It is clear that the arrangements and the associated systems and processes are lawful and, by and large, appropriate.
"The degree of uncertainty has made it difficult, in a review of this nature, to form a conclusion on whether the use made of the email was for such a related purpose. That, in turn, makes it difficult to say whether the established systems and processes were followed with regard to the email."
Deputy Mayor Nobby Clark said among the reasons the arrangement was put in place was so the council did not miss important meetings. In the past Sir Tim had failed to inform councillors and senior staff about meetings.
He believed it was the staff and Mrs Hadley’s duty to inform councillors if they found any issue or wrongdoing from anyone which could be inaccurate or damaging to council staff.
The mayor had on numerous occasions been encouraged by the chair's group not to make "inaccurate" statements to media .
So despite it causing "a little bit of angst among a couple of our colleagues" it was appropriate for Mrs Hadley to bring the email to the meeting.
Sir Tim said he felt vindicated by the report and his understanding was that Mr Buchanan had identified the email in question was personal information.
However, as he believed the findings of the document were inconclusive, he asked for a further review with a broader scope to consider the lawfulness of the interceptions.
"The scope of the current review sought to sweep the issue under the carpet by focusing on arrangements in place rather than the actions of the chief executive.
"I don’t like to sort of spoil the party because there is a lot of good work going on here — and everyone recognises that, but at the same time ... we should always aspire, I believe, to encourage people to speak out freely and openly about how they feel."
Cr Clark said he would oppose the further review as it would cost more money and said if Sir Tim was not satisfied with Mrs Hadley’s apology, he had other options to pursue the issue.
Cr Rebecca Amundsen put forward a recommendation on the report which stated the chief executive's actions in sharing the email with the chair's group was appropriate as per the findings of the report.
Councillors voted in support of the amendment with Sir Tim abstaining.
