The former chief financial officer of a southern Sydney council and a number of colleagues acted corruptly after the CFO was involved in raising more than $5 million in bogus invoices and charging more than $600,000 in personal expenditure on a council credit card, the state corruption watchdog found.

Former Botany Bay CFO Gary Goodman and a host of other council employees party to the rampant spending were found to have acted corruptly, the Independent Commission Against Corruption found in its report into Botany Bay Council on Wednesday, following a public inquiry last year.

Former Botany Bay Council CFO Gary Goodman leaves an ICAC hearing in March last year. Credit:James Alcock

A total of 12 other people, mostly other council employees, and a construction businessman had corrupt findings made against them; 10 of whom the ICAC will recommend the Director of Public Prosecutions consider laying charges against.

Mr Goodman's corruption extended over nearly two decades until 2015, when he was fired following the ICAC investigation.