Western Australia's corruption watchdog, John McKechnie, has threatened to resign amid controversy over a parliamentary committee's findings surrounding a misconduct investigation into three former state MPs.

Key points: Mr McKechnie is caught in a row between the Premier's department and a committee

Mr McKechnie is caught in a row between the Premier's department and a committee That row is over a decision to hand emails belonging to former MPs to the CCC

That row is over a decision to hand emails belonging to former MPs to the CCC The threat to resign comes Mr McKechnie was summonsed to appear

Mr McKechnie has also revealed he has been summonsed to appear before State Parliament's Procedure and Privileges Committee tomorrow afternoon.

It follows the committee's recommendation that two of Premier Mark McGowan's top staffers, including the director general of the Premier's department, face investigation over a potential contempt of Parliament related to a corruption investigation into the former MPs.

Mr McKechnie, the head of the Corruption and Crime Commission (CCC), is at the centre of a row between the committee and Mr McGowan's department over the disclosure of emails belonging to the former MPs.

A report by the committee said Department of Premier and Cabinet director general Darren Foster likely breached parliamentary privilege by giving the emails to the CCC, after it requested them as part of its ongoing investigation.

McKechnie worried he may find himself in contempt

In a letter by Mr McKechnie to Attorney-General John Quigley, he expressed serious concerns about the "broad nature" of the summons to appear before the committee.

He said the committee may ask him questions which would require him to breach the CCC Act or disclose information on the misconduct investigation relating to the three former MPs.

Mr McKechnie said he would not breach the CCC Act.

"I am personally concerned following the committee's earlier correspondence that I may be found in contempt of the House," he said.

"Before such an event I would of course reflect on my ability to continue to lead the commission."

Mr McKechnie is concerned about the "broad nature" of the summons. ( ABC News )

Mr Foster has also been summonsed to appear before the committee tomorrow and to produce copies of the emails and related documents which his department handed to the CCC.

The committee claims Mr Foster had no authority to decide which of the documents were covered by parliamentary privilege and which could be sent to the corruption watchdog.

The committee said it had devised its own procedure for determining what could be released to the CCC.

But in his letter, Mr McKechnie said "this exceeded the breadth of parliamentary privilege".

"Although I am sure it is not the intention of the committee to impede or obstruct the commission's investigation, that would be the effect," he said.

Premier, Commissioner back director general

Mr Foster's department took advice from the State Solicitor's Office regarding which emails and documents to release.

Mr McKechnie said Mr Foster had acted "very professionally and cooperated with the commission to the fullest extent".

Mr McGowan echoed the support of Mr Foster, saying he abided by the law and the CCC Act.

"The Government has done the right thing legally and the right thing morally, and I think the right thing by the public of Western Australia, in standing against potential corruption by former MPs," he said.

Liza Harvey claims Mr Foster's position is now untenable. ( ABC News: Andrew O'Connor )

But Opposition Leader Liza Harvey said Mr Foster's position was now untenable.

"Darren Foster has emerged as an untrustworthy gatekeeper of our private emails, emails from whistle blowers, emails from our constituents," Ms Harvey said.

"He has shown a casual disregard for keeping the security of our data intact and I'm really concerned about it."