North Wales Police chief constable Richard Brunstrom has criticised MPs for trying to keep their expenses secret.
Richard Brunstrom says he is a "passionate supporter" of openness
He described a bill to exempt MPs from the Freedom of Information (FOI) Act as an "almost bizarre" proposal.
But Mr Brunstrom also called the act a "pale, watered-down" imitation of such legislation in other countries.
He has updated his personal business expenses on the force's website after a FOI request by The Sun newspaper.
Writing on his blog, Mr Brunstrom described himself as a "passionate supporter of openness and transparency in public life".
He said he was "delighted" when the Freedom of Information Act was adopted in 2000, although he called it a "watered-down" version of similar laws in countries like the USA, Canada and New Zealand.
"We in the police accept it as the norm, and our democracy is much the better for it," he wrote.
He added: "Government departments seem to have more difficulty with it and are, as reported in the national press, often strangely reluctant to comply."
A private member's bill brought by Conservative MP David Maclean, which proposed exempting MPs from the FOI Act, was an "almost bizarre proposal", according to Mr Brunstrom.
He said: "The stated rationale is to protect the confidentiality of MPs' correspondence - a perfectly fair point, were it not for the fact that the existing legislation does this perfectly adequately already.
"Cynics are saying that the real intent is to prevent MPs' expenses being revealed" he added.
Should the bill become law, Parliament will have put itself in "the very odd and retrogressive situation of being less open than the Scottish Parliament and the Welsh and Northern Irish assemblies" he continued.
He said he could not believe that this is in the national interest.
The Sun newspaper had used the Freedom of Information Act to request details of his personal expenses.
However, that information - going back to 2005 - is already on the site and updated on a regular basis. Mr Brunstrom said in his blog that it will be updated every three months in future.
Records of Mr Brunstrom's expenses can be found under the "freedom of information" section of the website. Click on "information classes" followed by "chief officers expenses".