No evidence was given on whether concerns raised by opposition members over the Sixfields loan were investigated or resolved, auditors have reported.
But the damning report, compiled by Price Waterhouse Cooper, also states that opposition councillors at Northampton Borough Council had not "exercised their right" to call for the Overview and Scrutiny Committee to review the decision.
The report states that minutes of the cabinet meeting showed three opposition members had raised concerns.
The report states: "Suggestions were made that the report should be examined by the Overview and Scrutiny Committee with reference to the relocation of the athletics track, nature of negotiations which had been undertaken and potential legal challenges.
"The minutes demonstrate the Leader of the Council [David Mackintosh] had responded and 'explained that there had been numerous people involved in negotiations, including himself, cabinet members, the chief executive of Northampton Borough Council [David Kennedy] and the Section 151 Officer'.
"He further commented that he was happy that the decision was transparent and had been scrutinised by officers but emphasised that there was a need to make progress as soon as possible," the report added.
"No information has been provided which identifies whether these concerns were investigated and adequately resolved, and there is no record of the report having gone to the Overview and Scrutiny Committee.
"Opposition members could have exercised their right to request the decision to be reviewed by the Overview and Scrutiny Committee, however, they did not exercise this right," the report added.