Former Sydney councillor Salim Mehajer has been banned from managing corporations for three years due to high level incompetence.

The Australian Securities and Investments Commission (ASIC) took the step to safeguard public interest last year, but we are only hearing about it now because the details of the decision to ban him were publicly suppressed during an appeal launched by Mr Mehajer.

The Administrative Appeals Tribunal (AAT) has now upheld ASIC’s original decision.

The authorities slammed Mr Mehajer’s conduct in managing two corporations SMPD P/L and SMEC P/L, which “fell far short of what is reasonably expected of a director”.

They accused him of taking a cavalier approach to company management, saying he must be banned “in the public interest to protect others from his incompetence”.

ASIC commissioner Greg Tanzer welcomed the outcome of the appeal.

The regulator ruled that Mr Mehajer's ineptitude at managing corporations caused both property and construction companies to fail.

ASIC found Mr Mehajer did not keep adequate financial records, and ended up running companies that owed the tax office more than $1 million between them.

Mr Mehajer's conduct “lacked commercial morality”, ASIC said, allowing one company to collect GST of more than $300,000 from the sale of townhouses that was not declared to the ATO.

Mr Mehajer became a near household name after his 2015 wedding blocked Sydney streets.

He has since been beleaguered by court cases and allegations he had misused his position with the council for financial gain.

The AAT said the three year period of disqualification would give Mr Mehajer “time to properly acquaint himself with the duties of a director of a company and his obligations to those with whom the company may transact”.