An independent inquiry into claims of funding irregularities within the London Development Agency (LDA), has been demanded by the London Assembly.
An internal review cleared Lee Jasper
An internal LDA review cleared Lee Jasper, the mayor's head of equalities, over Evening Standard claims about the funding of black organisations.
However, assembly member Bob Blackman branded the report "unsatisfactory".
The mayor's office said the report had been sent to the district auditor to decide if further action was needed.
Mr Blackman proposed Wednesday's motion to refer the LDA to the district auditor to investigate the allegations.
He said: "The district auditor must conduct a properly independent and completely thorough review of all the relevant information relating to this issue".
In December the newspaper alleged hundreds of thousands of pounds paid to the groups by the mayor's LDA are unaccounted for.
An internal inquiry conducted by the LDA cleared Lee Jasper of any wrong-doing.
But assembly members criticised the report for having "huge gaps in what it actually covered and the evidence it was based on".
A Greater London Authority spokesperson said it was "illogical" as the LDA review had already been sent to the independent district auditor.
She said: "It is for the district auditor to determine how he wishes to proceed and not for political figures, such as members of the London Assembly, to attempt to dictate this.
"This statement is a clear political attempt to interfere with the work of the district auditor."