Gay, 70, pleaded guilty to the charge on the basis that he ought to have known the 2009 sale that netted around $3 million was illegal.

Justice David Porter said in sentencing Gay that he ought to have exercised far greater care in making the sale, which was influenced by the state of his health.

Justice Porter accepted that Gay was of exemplary character, and having learnt he had prostate cancer, decided to get his affairs in order and reduce debt.

But the December 2009 sale of 3.4 million shares at 90 cents was made after company directors learnt of a slump in Gunns revenue, and before the information was released to the share market in the company's February 2010 half yearly report.

This was "high grade" information, Justice Porter said.

"I hope that I have made clear to you the seriousness of insider trading," he said.

Gay released a statement to the media a short time ago.

In it, Gay said he was looking forward to spending more time with his family and focusing on his health following the conclusion of court proceedings.

Gay said that the past four years had been among the hardest of his life.

"I'm looking forward to enjoying time with my wife, children and grandchildren, working on my farm and focusing on my health," Gay said.

"My family and I would like to sincerely thank so many people who have offered their support and friendship during this time.

"I hope all people respect my privacy as I work through treatment for my ongoing battle with cancer."