A 91-year-old man arrested at Sydney Airport last month with 4.5 kilograms of cocaine says he had no idea the luggage he was carrying contained drugs.

"It was soap — I opened it up and scratched it and it certainly was soap but it had some white streaks in it, which I am told was cocaine," Victor Twartz told 7.30 after appearing in court this morning.

According to police there was cocaine worth more than $1 million inside 27 bars of soap in a bag given to Twartz by people he met on an all expenses paid trip to India.

"They ... took me to the airport and gave it to me at the last minute," Twartz said.

Victor's son, Peter Twartz, said his father was caught up in a scam.

"He was going over there to sign a business contract that would release some funding to him and that is why he was going," he told 7.30.

"There was some $10 million of inheritance that would be freed up and released to him.

"The soap were gifts for the bank manager at this end that would be clearing the funds."

Cocaine was hidden in 27 packages of soap. ( Australian Federal Police )

Peter said his father is a devout Seventh Day Adventist with no criminal background.

"His background is as a dentist, he is significantly religious," he said.

"There is no way that he would knowingly [have] anything to do with drugs — he sees it as a scourge."

Victor Twartz is the latest in a long string of people lured by west African crime syndicates which use email scams to groom the vulnerable — the elderly, frail, mentally ill and juveniles — into becoming unwitting drug couriers.

"He had been targeted for some time," Australian Federal Police (AFP) Commander David Stewart said.

"These syndicates often target the lonely and the vulnerable among people within our society, and build that rapport, that trust.

"It's very much based on that loyalty that led them into that tangled web."

Peter Twartz said that fit the pattern in the case of his father.

"They have been communicating with him for some time, building up his confidence in them," he said.

"They hassle them, they will ring them at the middle of the night, they will ring him and hassle and hassle and hassle him.

"[They] get him all stressed and he ends up doing what they want him to do."

Space to play or pause, M to mute, left and right arrows to seek, up and down arrows for volume. Watch Duration: 7 minutes 10 seconds 7 m Victor Twartz's arrest has raised concerns about the way criminals are duping people.

AFP issues fresh warning about danger of drug-mule scams

The AFP issued a warning to those who may be tempted by similar scams.

"Regardless of your age, you can be targeted for exploitation from these organised crime groups - with no exception to sex, age or religious persuasion," Commander Stewart said.

"They are all about exploiting people and many of these people have been used in these scams."

Commander Stewart revealed 40 people have been arrested in Australia over their involvement with these groups.

Two thirds of the people dealt with by Australian courts were eventually cleared of wrongdoing, but usually after a lengthy stint in jail.

And there are dozens of others who have been arrested overseas after being lured by the drug syndicates.

"We're aware of 55 who have been interdicted internationally, and there are a range of countries," Commander Stewart said.

"The majority of those [are] probably sourced from south-east Asia because of the proximity to Australia."

Victor Twartz said he believed he would not go to jail but is not concerned if he does.

"As far as I'm concerned, I'm very glad that Customs had found it because I'm very against the young people taking drugs and it means that that much was stopped from getting to them," he said.