Tony Blair has paid a "heavy price" for ignoring the importance of upholding standards in public life, Sir Alistair Graham has warned.
Sir Alistair said the government is now considered sleazy
The Committee on Standards in Public Life chairman said the prime minister saw standards as a "minor issue".
Sir Alistair told the Sunday Times Mr Blair had made "a major error of judgment" by ignoring the subject and Labour was now considered "sleazy".
Education minister Jim Knight said Labour took "sleaze" seriously.
Sir Alistair also expressed concern about John Prescott's alleged affair with a secretary.
"Opinion polls [show] the public think this government is as sleazy as the last," he said.
"He [Mr Blair] has paid a heavy price for ignoring standards. We would have preferred more positive support from the prime minister.
"We suspect he is pretty lukewarm to the work we do."
'Cobbled up affair'
Sir Alistair also called the appointment of Sir John Bourn as an adviser on ministerial conflict of interest, a "cobbled up affair".
Sir John was appointed in March to advise ministers on potential clashes between their public duties and private affairs - and to investigate any claims that the rules have been broken.
But Sir Alistair told the newspaper: "He has hardly any discretion to intervene on his own initiative and there is no guarantee that any report he produces will be published."
He later told Sky News's Sunday Live programme: "While Sir John Bourn is a man of the highest standing, he has no discretion to intervene in his own right - he has to wait until he is be asked to intervene by the prime minister."
He added: "The government has not given an assurance that when Sir John is replaced there will be consultation with the opposition."
But Mr Knight pointed out that Sir Alistair was appointed by the prime minister.
He told BBC1's Politics Show Mr Blair had set up a "whole new" process of monitoring and reporting on these issues which showed "quite how serious" he was about cleaning up politics.
Mr Knight added: "The fact that some of these things have come to light that have raised widespread concerns have precisely been because we take it seriously enough to disclose these things."
He said he thought the "right moves" were now being taken in concern of the furore around fundraising for political parties.
Before Sir John's appointment, top civil servants in each government department had advised ministers about conflicts of interest. The Cabinet Secretary has investigated breaches of the ministerial code.
Sir John's appointment followed claims about Tessa Jowell and her husband's affairs. Mr Blair cleared Ms Jowell of any wrongdoing.
Sir Alistair's comments come as Scotland Yard detectives continue to investigate claims that peerages were awarded in return for loans or donations to Labour Party funds, or for sponsoring Mr Blair's flagship city academies.