A relative of Schapelle Corby says the convicted Australian drug smuggler's late father was part of the drug trade in northern Queensland for three decades.

Corby is currently serving a 20 year sentence after being found guilty of smuggling marijuana into Bali.

Before his death, Michael Corby Senior repeatedly denied he had anything to do with the drugs found in his daughter's possession in Bali.

His cousin Alan Trembath says that in the eighties Mr Corby was well known as a drug dealer in Mackay.

He says Mr Corby moved large amounts of marijuana throughout the area.

"He said do you want to earn eighty grand? Eighty grand I said what do I got to do, go and kill somebody for it and he said no, no," Mr Trembath said.

"Get you to take a boat up to see the bay and pick up a lot of marijuana and bring it back to Mackay and you'll get eighty grand for it. "

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