Some allegations reported to the investigators were so serious they have been referred for investigation to the Crown Office in Scotland - with the possibility of prosecution.
The 32-page report was presented to the district council last night and the meeting was immediately adjourned until 23 June so councillors could study it.
Professor Robert Black QC, of Edinburgh University, was asked to investigate the Labour-held council after allegations of corruption, nepotism and sectarian bias over the past five years. There were allegations of a so- called Monklands Mafia - a ruling Labour cabal which was in charge.
Prof Black's inquiry was due for completion by February, but he said the amount of work involved meant it took far longer than expected.
As he left the council buildings in Coatbridge last night, he said he was confident the authority had cooperated fully with him. While admitting there were a number of "loose ends", he said: "I think it has been worthwhile. Serious allegations were always likely to involve criminal conduct and I could not have investigated these."
In the report he agreed with the long-held public view that there was evidence of far more money being spent on Coatbridge than on Airdrie.
In council jobs there also appeared to be a bias between the two towns. In one example, where concierge staff were recently taken on, 32 were from Coatbridge and six from Airdrie.
Prof Black said the application form should not ask for the exact address of applicants.
He also highlighted the large number of appointments given to members of the Labour Party or their families.
But some areas of the council were cleared. He ruled out criticism of planning decisions and said the department could justify its recommendations. He added that the high number of complaints about housing could be because of the complicated allocation system.
He said there was evidence that councillors who were council tenants had preferential treatment in housing repairs being carried out quickly.
Senior Labour Party officials will discuss the implications of the Black report in London today amid concern that it could damage the party, which has campaigned against "sleaze" in government.
Jack McConnel, general secretary of the Scottish Labour Party said last night: "This is a serious report which demands serious action. It names no names so the action will have to be carefully considered, but we must never allow this situation to develop in the Scottish Labour Party ever again."
Controversy has been heightened by the area's links with John Smith, the late Labour leader, who represented it in Parliament.
Helen Liddell, the Monklands East Labour MP elected after the death of John Smith, said: "The report backs up an awful lot of what I was saying last year during the by-election."Reuse content