The embattled Alberta Securities Commission (ASC) is replacing yet another member of its senior management team following the resignaton of general counsel Denise Hendrickson.

In an internal memo to staff obtained by The Canadian Press, interim ASC chairman Peter Valentine said Hendrickson is leaving by the end of the month to pursue a "tremendous opportunity" in the private sector.

Hendrickson's position will be temporarily filled by Kari Horn, who has been with the ASC's legal office for two years.

The general counsel provides research and advice on ongoing issues such as corporate governance, certification of companies' disclosures and the separation of chair and chief executive functions.

Hendrickson's resignation is the third of eight senior management positions to come vacant in the last month at Canada's second-largest market regulator.

Earlier this month, former chairman Stephen Sibold's five-year term expired. He was replaced by Valentine.

In April, the former head of administrative services, Grahame Newton, was fired for failing to co-operate with a KPMG forensic audit aimed at checking security and confidentiality of the commission's computer systems.

Newton has since filed a wrongful dismissal suit against the commission in which he claims his termination was "retribution and reprisal'' by top commission officials after he'd been identified as a whistleblower "regarding certain activities at the market regulator.'' The ASC has said Newton was fired from his $160,000-a-year job for cause. It says his firing had nothing to do with his raising concerns about enforcement practices and the working environment.

In recent months, high-profile allegations of interference with enforcement proceedings and harassment of staff have dogged the ASC, which oversees most of Canada's largest energy producers, along with such major companies as Canadian Pacific Railway and WestJet Airlines.

Last month, Alberta Finance Minister Shirley McClellan asked the province's auditor general, Fred Dunn, to expedite an investigation of the ASC and report his findings by July.

But the commission has challenged in court Dunn's authority to conduct a so-called "systems audit.'' The ASC says such a review would infringe on privacy rights that are guaranteed by Alberta's securities legislation.

A ruling on whether Dunn can proceed with his audit is expected shortly.

The market regulator's troubles also threaten to halt two of its longest-running enforcement hearings.

Former executives of Blue Range Resources have applied to have their 126-day hearing stopped.

They argue the regulator protected friends, kept material information from the defence and offered immunity to key witnesses.

And former executives of Proprietary Industries filed a similar application alleging that a "circus-like atmosphere'' surrounding the ASC has destroyed any possibility that the applicants will be able to receive a fair hearing.

Both applications are to be heard by an ASC panel in early June.

However, McClellan said that the business community has confidence in the commission.

"The Alberta Securities Commission handles up to 2,000 files in a year,'' McClellan told The Canadian Press in an interview last week.

"Now if you had one or two (complaints) ... out of 2,000, it would be hard to justify the statement that the wheels are falling off.'' McClellan also said the government believes the interim commission chairman will sort out the issues that have been nagging the securities commission for several months.

"We will resolve the human resource issues, which are very real,'' she said.