One of Australia's largest real estate networks is facing internal upheaval amid allegations of mismanagement, manipulation of books and possible conflicts of interest including deals with suppliers owned by or linked to its own board members.

In recent months, a reform group of disgruntled First National Real Estate agents has called for a forensic audit of the company's books for the past five years under the company's chief executive, former Melbourne Football Club boss Ray Ellis.

First National has hundreds of branches across Australia and New Zealand. Credit:Eddie Jim

As part of the push for change, a former finance manager has written to the corporate regulator admitting his role in falsifying First National's accounts to improve the company's financial position.

In a confidential 2014 letter to the Australian Securities and Investments Commission obtained by Fairfax Media, former finance manager Darren Moon says that in the years 2010-2011 he was "required" by Mr Ellis to "adjust" financial reports and "overcapitalise the balance sheet by manufacturing figures". During 2012-2013, First National was teetering on insolvency.