Ashley De Malmanche said his father was "a bit of an internet dater" and had met a new woman about three months ago.
"She lives South Africa or somewhere. She said she would pay for his trip. I said to him 'look, this is dodgy, people don't just do that kind of thing - there is no such thing as a free lunch'. But he went.
"He said he didn't have any clothes and she said not to worry, she would buy him some. She sent him the money for the tickets. He said he didn't have a passport so she sent him the money to get one... that's why he didn't think it was a scam.
He's been a bit silly."
Ashley De Malmanche said his father did not use methamphetamine or any other drugs except for painkillers. In 2002 he was working as a tree feller and a large branch struck him, resulting in serious back and neck injuries.
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He has been unable to undertake any physical work since, and is still in a lot of pain.
His son was worried that he would not have access to his medication in Bali.
"He's probably going to be in a lot of pain, even at home he is in pain."
"He's never used that stuff (methamphetamine). He's a good person."
At a press conference in Denpasar yesterday the airport's head of customs office Budi Harjanto told reporters De Malmanche was acting suspiciously when retrieving his luggage on Monday.
"From X-ray examination, we found something suspicious in his green backpack. After checking, we found a package with clear plastic wrapping, wrapped again with red plastic and brown duct tape. Inside, there's clear crystal weighed 1.709kg total."
A narcotics test confirmed the crystal was methamphetamine.
De Malmanche has been charged with a section of Indonesia's strict narcotics law carrying a maximum penalty of death and a one billion rupiah ($104,731 NZD) fine.
Mr Harjanto said De Malmanche was supposed to meet a woman at the airport. She was reportedly his fiancee and was on a different flight to Bali.
Mr Harjanto speculated that De Malmanche was set to marry the woman in Bali after meeting with her in Hong Kong.
Last night Ashley De Malmanche was not sure what he could do to help his father. He did not know whether he would be allowed to contact his father - or how.
"There's not much we can do. He can't afford a lawyer and we won't be able to afford on either. I'm not too sure what we can do,' he said.
"This is the first time he has been out of the country I think. To be honest, I would have tried harder to stop him from going if I thought he would actually do it - I didn't think he'd be able to get himself over there."
As of last night De Malmanche had not requested consular assistance from the Ministry of Foreign Affairs and Trade. The agency were aware of his arrest but had not been contacted by him or any of his family.
De Malmanche's arrest comes soon after Kiwi Leeza Ormsby was deported from Bali, where she spent nine-months in jail for posession of marijuana. Ormsby was incarcerated in the notorious Kerobokan prison, where high profile Australian drug smuggler Schapelle Corby served her sentence.
