Barry James Calverley was stopped by border force officials at Sydney International Airport on a flight from Laos via Vietnam on January 24, 2024.
He was carrying a green bag containing a camp bed with mosquito net which had 48 packages of heroin hidden within the metal frame.
The 70-year-old pleaded not guilty to one count of importing a commercial quantity of a border-controlled drug as his trial started Monday in Sydney's Downing Centre District Court.
Commonwealth prosecutor Sheridan Goodwin told 12 jurors that the total weight of pure heroin within the camp bed was around 2.5kg.
While there is no dispute Calverley brought the drugs into Australia, the main issue for the jury to decide will be whether he knew he was carrying them.
Jurors heard the 70-year-old received an email in late 2023 saying there was a payment waiting for him of over $14 million.
He was told to contact someone purporting to work at a UK-based payments centre.
He was then directed him to pick up documents overseas before he could obtain a then reduced payment of around $10 million in Australia.
Calverley was told an investor would cover his flights and accommodation before flying to the Laotian capital of Vientiane on January 16, 2024.
The 70-year-old believed what he was being told, thinking the millions of dollars offered was a form of compensation after being scammed of $260,000 in 2022, his barrister David McCallum told the jury.
"(He was) duped or tricked into becoming an innocent drug mule," the barrister said.
Prosecutors dispute this, saying Calverley knew the bed concealed a substance and that he was reckless to the fact the substance was a border-controlled drug.
The 70-year-old sat in the dock wearing a hearing loop during the trial as his daughter Harriet Calverley attended in support.
The jury heard on arriving in Vientiane, Calverley met who he described as "African men".
He was given a "gift" of the camping bed to be taken back to someone called the paymaster general in Sydney.
After the drugs were discovered at Sydney airport, he said he needed to speak with federal police or the border force boss in a private room.
"I need to show them something on my phone which will explain everything," he told the officer who stopped him.
"I didn't know what was in the bag. I'm innocent,' he told her supervisor.
However, he also claimed he purchased the camp bed for $58 as a gift for his wife.
The trial continues on Tuesday and is expected to run for at least five days.
