The authorities became suspicious after finding 27 packages of soap in the suspect's luggage when he flew from New Delhi last month, officials said Tuesday.

"Presumptive testing of the soap showed positive readings for cocaine," police and the Australian Border Force reported, adding that the total amount of cocaine exceeded 4.5 kilograms (10 pounds).

The retired surgeon appeared in a Sydney court on Tuesday and was released on bail. He is set to appear in court again in October.

If convicted, the 91-year old could face life in prison.

'Personal responsibility'

The suspect claims he was handed a bag by acquaintances in New Delhi, who told him it contained gifts for someone in Australia, according to the country's broadcaster, ABC.

However, claiming ignorance is not enough to avoid criminal prosecution, according to acting assistant commissioner Wayne Buchhorn.

"People can expect they will be charged if they knowingly bring drugs into Australia, or are reckless or willfully blind to the fact that there could be narcotics concealed inside their luggage or items they are carrying," Buchhorn said.

Police did not specify whether the elderly man was aware of what he was carrying, but the case prompted the authorities to urge citizens to be careful.

"Luggage is a personal responsibility. If you've been asked to carry something on behalf of another person, be sure you know exactly what is inside," senior Australian Border Force commander Tim Fitzgerald said.

dj/kms (AP, AFP, dpa)