Vision Montréal leader Louise Harel, left, and city councillor Pierre Lampron speak in Montreal Tuesday. (CBC)The opposition at Montreal City Hall is demanding action following revelations that a senior bureaucrat was spying on the auditor general's emails.

Vision Montréal leader Louise Harel is demanding Mayor Gérald Tremblay fire controller general Pierre Reid after it was revealed Reid was conducting a controversial investigation into Auditor General Jacques Bergeron.

Projet Montréal leader Richard Bergeron has already accused the mayor of conducting a "witch hunt" because of the revelations, and both opposition parties said future reports by the auditor general could be called into question.

The allegations stem from revelations that, in 2009, the head of the city council's audit committee began an investigation after receiving an anonymous tip about possible misconduct by Jacques Bergeron.

The committee is made up of five elected officials and two independent auditors, and the head of the committee is André Harel, one of the independent auditors.

The tip suggested that Bergeron had awarded two $2,500 contracts to family members, which would break the city's ethics code.

Auditor General Jacques Bergeron during a 2010 investigation into the city's contract with Telus. (CBC)It was a year when Bergeron was closely scrutinizing the city's controversial water meter contract.

But audit committee member and opposition councillor Pierre Lampron said the committee had decided to investigate Bergeron himself, without telling the elected members of the committee.

He said André Harel asked Reid to examine Bergeron's emails over the course of a year, when the committee head should have referred the the matter to the province.

"What is unacceptable is to know that during one year someone within the organization and very near the top of the decision-making of the municipality has had access to everything," said Lampron.

We didn't know: administration

Lampron said he and other members of the committee, including elected members of the Tremblay administration, only found out about the investigation earlier this month.

In a statement released Monday, a Tremblay spokesperson said the mayor learned of the matter only a few days ago.

But the Projet Montréal leader said the mayor had to have known about the investigation, and yet did nothing about it.

Fellow opposition leader Louise Harel said Reid's actions were illegal, and Tremblay should act.

"[The mayor] must punish a completely reprehensible action, because a trust is broken here," said the Vision Montréal leader.

The city's auditor general agrees, calling the actions an "illegal intrusion."

In a letter sent to all city council members, Jacques Bergeron said bureaucrats investigating a complaint against him tried to camouflage the fact that they were reading his emails.

Bergeron said that shows that the investigators knew what they were doing was illegal.