OTTAWA - Whistleblower protection groups are demanding the Harper government dump its second consecutive public service integrity commissioner after two damning audits of his office.

The auditor general has found "gross mismanagement" of two separate case files in the troubled Office of the Public Sector Integrity Commissioner of Canada, which was created by the Conservative government in 2007.

"It sounds so familiar, this story did not surprise," Allan Cutler, a civil service whistleblower on the Liberal sponsorship scandal, said in an interview.

Cutler has been battling for better protections for years.

Christiane Ouimet, the first federal integrity commissioner appointed by Prime Minister Stephen Harper, resigned in disgrace in 2010 before a scathing audit found she had failed to fulfil her mandate and had mistreated her staff.

Her successor, Mario Dion, vowed to clean up the office, which is supposed to protect public servants who blow the whistle on wrongdoing within the federal government.

But a judicial review of a case in 2012 found ongoing problems with how complainants were handled, and now auditor general Michael Ferguson has waded in after getting a request from two more unsatisfied whistleblowers.

"We found the actions and omissions of PSIC senior managers (the commissioner and deputy commissioner) in relation to this file amount to gross mismanagement," Ferguson reiterated for each of the two in a report quietly posted last Friday.

Dion issued a statement Tuesday saying his office had tightened up case file oversight even before the latest audit.

"I agree there were unacceptable procedural delays in dealing with two older case files before my office and I want to assure federal public servants that we are doing our utmost to make sure this does not happen again," Dion said.

The office changes "make it almost impossible to have a repeat of the incidents cited by the auditor general," he added.

The details of the two whistleblower concerns and the alleged reprisals against them by their managers are not included in the audit, which examined how the files were handled.

One case dragged from 2008 until April 2013, while another dated from 2009 and was only closed this January. Both were ultimately dropped without actions being taken against alleged wrongdoers in government.

Ferguson stresses in the audit reports, quietly posted last week, that they focus on specific cases and not the overall operations of the office. Nonetheless, his assessments are unsparing.

The audit criticized buck-passing by top managers, the slow handling of cases, the loss -- twice -- of the same confidential file, poor handling of conflicts of interest, and even the inadvertent identification of a whistleblower to the alleged wrongdoer.

Three whistleblower advocacy groups say the audit shows the integrity commissioner's office remains a "black hole," where allegations of wrongdoing routinely disappear.

"Dion has failed, in my opinion, at least as badly as Christiane Ouimet," said Cutler, who heads a group called Canadians for Accountability.

He contrasted the Conservative government's criticism of officers of Parliament such as chief electoral officer Marc Mayrand with its silence on the integrity commissioner.

"I think there needs to be a change of leadership," said David Hutton, executive director of the Federal Accountability Initiative for Reform, or FAIR.

He said Ouimet and Dion are both lifelong bureaucrats who come from a culture where protecting those above you is a career-enhancing prerequisite.

"Now you're putting these people in a position where their job is to expose wrongdoing which will embarrass their deputy minister and departments, if it's done properly," said Hutton.

"So you're asking them to do something that is completely against their instincts."