Media icon Ita Buttrose says she was absolutely shocked to learn of her nephew's drug use, after he was caught with almost six kilos of cocaine and $1.3 million in cash.

Giving evidence at Richard Buttrose's sentencing hearing on Thursday, Ms Buttrose said he was "the last person in the world" she would have thought used or sold drugs.

Her nephew told the judge that to his circle of friends using cocaine was "just like having a glass of wine" and how he became "obsessed" with the drug.

A psychologist testified that Buttrose told him he was known as "the man" and his cocaine dealing led to acceptance in the "wider echelons" of eastern Sydney society.

"He was never particularly motivated by money or greed, but rather by a craving for affection," said Dr Donald Roe - an opinion challenged by the crown.

Buttrose, 36, of Paddington, is facing a substantial jail term after pleading guilty to two counts of supplying cocaine to an undercover officer and another relating to the discovery of almost six kilograms of the drug in his Darling Point unit.

The two bricks of cocaine had a potential street value of up to $10 million.

Police also found $1.3 million in cash, the NSW District Court hearing in Sydney was told.

Ms Buttrose said her nephew lived near her, she regularly saw him at family functions and was aware that he had become a successful restaurateur.

She was "absolutely shocked" to learn he was taking drugs, but was now convinced he would "not walk this criminal path again".

Ms Buttrose said she would continue to support her nephew.

Breaking down while giving evidence, Buttrose said he began using cocaine in 2003 and became a regular user, along with a lot of the people he mixed with.

While not justifying its use, Buttrose said no one seemed to think it was a problem and in that environment "you don't feel you are doing the wrong thing".

His use of the drug increased, he built up a small debt, asked his dealer for a discount and "it grew to more and more people asking for cocaine".

"There was an excitement to it," he said.

"Before I knew it, there were large amounts of cocaine and I had lots of friends asking for it."

He denied being motivated by greed and said he never told anyone he had the drug, which was for friends.

In response to Judge Robert Sorby asking about his supply to an undercover policeman, Buttrose said the man had been introduced by a friend.

He denied being a "major supplier", or helping authorities after his arrest "to save yourself".

Buttrose said his life was "out of control" and he realised he had an obsession with cocaine.

His uncle, Charles Buttrose, a senior constable in the NSW Police Force, also gave evidence.

He said he had seen people under the influence of drugs, but had never noticed his nephew in such a state.

Buttrose is due to be sentenced on December 4.