The head of WA's corruption watchdog has likened his failure to be reappointed to a "decapitation" of the organisation, amid allegations by the state's Premier a probe of parliamentary expenses is behind the decision.

Key points: A committee made up of MPs rejected the re-appointment

A committee made up of MPs rejected the re-appointment But it denies this was due to a probe of parliamentary expenses

But it denies this was due to a probe of parliamentary expenses The Premier says the move is "self-interest" by the Liberal Party

Corruption and Crime Commission (CCC) head John McKechnie's time in the role appears over, with the parliamentary committee responsible for choosing the organisation's commissioner again vetoing a State Government attempt to extend his term by five years.

Mr McKechnie's position will now expire on April 28, ending a five-year term that has seen him lead high-profile investigations — including scrutiny of the Department of Communities, North Metropolitan Health Service, Tokyo trade office and MP expenses.

"I have to say I've seen some strange political things in my time, and this is probably up there as a gold medal contender," Mr McKechnie told ABC Radio Perth.

"Why anybody would think it's a good idea to decapitate the corruption commission when it's in the middle of about seven or eight major investigations, I don't know."

In a statement earlier today, the parliamentary committee overseeing the CCC said it was "unable to reach either a bipartisan or a majority decision", meaning opposition came from at least two members of the four-person body.

In an earlier decision, it said it had only failed to reach bi-partisan agreement.

Sorry, this audio has expired Listen to the full interview here: WA corruption chief likens leadership situation to decapitation of the agency

The committee is made up of Labor MPs Margaret Quirk and Matthew Hughes, Liberal MP Jim Chown and Greens MP Alison Xamon.

Mr McKechnie said he was still unaware of the reasons why the committee failed to agree.

"It seems to me we face a wait of months before a new commissioner can be appointed," he said.

"And if anybody thought getting rid of me will stop the work, I think they'd be sadly mistaken, because whoever takes over will continue that work."

Mr McKechnie said he would have liked to have continued in the role.

"I do think I have something to offer the state in terms of wisdom and guidance of these important investigations — others have made the decision that is not going to happen."

Claims veto linked to Parliament probe

In the statement issued today, committee chairwoman and Labor MP Ms Quirk slapped down commentary from within her own party's leadership — remarks made by Premier Mark McGowan and Attorney-General John Quigley — alleging improper motives with the vote of Liberal MP Jim Chown, labelling it "unfounded public speculation".

Mr McGowan and Mr Quigley had alleged Mr Chown vetoed against Mr McKechnie's re-appointment because of the CCC's investigations into Upper House Liberals including Phil Edman.

A CCC investigation found former WA Liberal MP Phil Edman's $700 trip to a Japanese bathhouse called "Soapland" was paid for with state funds. ( ABC News )

Under committee rules, the votes of individual MPs are kept secret.

"Because of unfounded public speculation about the motives for the committee's previous deliberations, it has resolved to unequivocally reject any suggestion that the motivation for any members not supporting the appointment recommendation was the Corruption and Crime Commission's focus on parliamentary electoral allowances," Ms Quirk's statement said.

A CCC report issued under Mr McKechnie also said Mr Edman used his electorate allowance to pay for berthing fees for his yacht, the "Prime Minister". ( Facebook: Phil Edman )

"Discussion on what did or did not occur in the committee, and imputing motives to individuals, does not progress a constructive way forward.

"The nature of those discussions is not detailed because it includes information provided by third parties in confidence."

Ms Quirk said all three nominees put forward for the role of CCC commissioner were described as "qualified for appointment to the position", also pointing out that commission appointees had been blocked previously.

Comparisons with Untouchables boss

The Government has remained adamant Mr McKechnie should be re-appointed.

Mr McGowan said Mr McKechnie's re-appointment being blocked again was "very frustrating and very, very concerning".

WA Premier Mark McGowan wants to change the appointment process for the CCC commissioner by passing legislation. ( ABC News: Nicolas Perpitch )

"He has been a corruption fighter unlike any we have ever seen before in Western Australia," Mr McGowan said.

"Mr McKechnie has been the Eliot Ness of Western Australia.

Ness was an American federal agent famous for his efforts to bring down Al Capone and enforcing prohibition in Chicago in the 1930s.

Mr McGowan again took aim at Liberal MPs, claiming it was their fault the re-appointment had been blocked.

"How can you have someone who has been so successful in uncovering corruption blocked by people with self-interest in blocking his re-appointment?" he said.

"It is wrong and it is outrageous."

Former Department of Communities assistant director general Paul Whyte was charged with misappropriating $22 million from the public purse after an investigation by the CCC last year. ( ABC News: Hugh Sando )

The Government's only hope of Mr McKechnie's term being extended is if State Parliament passes extraordinary legislation to keep him in the job, a step that is extremely unlikely given the Liberals, Nationals and key crossbenchers have all voiced their opposition — meaning Labor would not have the numbers to get it through the Upper House.

The Greens are yet to decide a position but leader Alison Xamon said this represented an "unprecedented attempt to bypass appropriate channels" and was "deeply disturbing".

All five conservative crossbenchers have indicated they either would or were likely to vote against the legislation.

With the Liberals and Nationals opposed, the Government would need the support of the Greens and at least one crossbencher.

WA Liberal Leader Liza Harvey said while she "unequivocally supported" the reappointment of Mr McKechnie, she did not get a vote on the committee.