A property developer and Liberal politician on Sydney's most controversial council has been fined just $3600 for building an apartment block with too many bedrooms.

Auburn City Council has issued the penalty to a company owned by suspended councillor Ronney Oueik, who made millions building and selling units in a complex that breached its development approval.

Former premier Mike Baird on the 2015 campaign trail in Auburn with the party's candidate Ronney Oueik, a former Auburn councillor. Credit:Brendan Esposito

As revealed by Fairfax Media in March, council staff had known for years that there were "irregularities" with Cr Oueik's Station Road complex, where most of the approved two-bedroom units were found to actually contain three bedrooms.

But the council only fined BBC Developments for the "illegal internal non-structural building works" following repeated enquiries by Fairfax Media – and eight years after the council was advised to take legal action against Cr Oueik's company, but did nothing.