HP CEO and president Mark Hurd has confirmed that he approved a probe of HP employees, board members and journalists in an effort to find out who on the HP board was leaking confidential information outside of the company.

However, Hurd said he did not approve the placement of tracing technology in an email to a journalist, and apologised for this and any other 'inappropriate' tactics - such as physical surveillance and obtaining phone records under false pretenses, known as 'pretexting' - that HP undertook in its investigation to find the source of information leaks.

"I extend my sincere apology to those journalists who were investigated and to everyone who was impacted," Hurd said. "The inappropriate techniques that were applied do not reflect the values of HP... these are not indicative of how we conduct business at HP."

Hurd also said he accepted the resignation of Patricia Dunn from her position as chairman of the HP board and a director, effective immediately, and thanked her for her eight years of service on HP's board. Previously, Dunn was to stay on as a director of the board, but would step down as chairman in January. Hurd now takes on the role of chairman of HP's board.

HP also appointed Bart M Schwartz, a former US prosecutor, as board counsel. His role will be to perform an independent review of investigative methods and the company's Standards of Business Conduct processes, and to make future recommendations for implementing best practices. He will report to Hurd and HP chief financial officer Bob Wayman.

Hurd said that HP had the "best intentions" when it began the first of two phases of a probe into boardroom leaks, but said it "turned in a direction we could not have anticipated" and he takes full accountability for what transpired.

"I take this very seriously and commit to getting to the bottom of this," he said. "Our job is to fix this and get back to the job of running the business."