Conman Peter Foster has been sentenced to three years' jail for breaching a court order banning him from the weight loss industry.

The Federal Court in Brisbane ordered that Foster serve at least 18 months of that sentence behind bars.

The court was told Foster was involved in a scam involving a diet nasal spray in 2009.

He did not appear for today's sentencing, and also failed to appear at a previous hearing.

A warrant has been issued for his arrest.

Foster's lawyer Terry Fisher withdrew his representation this morning.

He says he has been in touch with Foster, but does not know where he is.

"Yes I have had contact," he said.

"The last I saw him there was a palm tree waving in the background so I'm not sure where he is."