When Gary Kurzer’s day in court against the Australian Tax Office finally arrives in September, he believes he will be fighting for thousands of ordinary Australian taxpayers.

The Sydney man says he lost his business, his home, his marriage and his health trying to fight the legal might of the Tax Office after a botched tax bill based on ''incorrect methodologies'' sparked a eight-year legal dispute.

Gary Kurzer Credit: Brendon Thorne

The struggle that began in 2006 with a bill for $200,000 in tax and penalties – later corrected to just $8000 – will culminate in a Federal Court showdown in Sydney in September, when the former architect will try to win $5.8 million in damages for the Tax Office’s alleged negligence.

The Tax Office, in its legal defence, says Mr Kurzer’s case is weak and that he will be unable to prove the Tax Office owed him a duty of care, but declined on Wednesday to publicly to discuss the case.