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A Chinese man was bound with chains and tortured with an array of instruments including a mallet and pliers during a terrifying ordeal that lasted more than two days, a Perth court has heard.

The man, who was in his late 60s, had flown to Australia in April last year believing he was going to be involved in a business deal.

Instead, he was detained for 50 hours in suburban Perth, and tortured with a dog collar that emitted electric shocks, a mallet, a sewing needle and pliers in what the prosecutor described as a series of sickening acts "normally reserved for a Hollywood movie".

The man was forced to contact his son in Sydney and demand he pay millions of dollars to his kidnappers, before he was ultimately rescued by police.

Cheng Xin, Zhaohe Ge and Te Putu Tonga Patara Te Tuhi Hawkings, all in their 30s, pleaded guilty in the District Court to detaining someone, demanding property by threats and endangering life.

'You are going to die'

The court heard Ge and Hawkings had met while working in the mining industry and had decided to go into business together with a purported plan to bring Chinese investors to Australia. Xin joined them.

They invited the Chinese victim to Australia on the pretext of convening a board meeting to discuss a Chinese project, then detained him at a home in suburban Caversham when he got to Perth.

Prosecutor Nikki Conley said the victim was punched, blindfolded, bound with padlocked chains and forced to sign papers saying he was a spy for the Chinese government.

The court was told Xin tried to force methylamphetamine and cannabis into the man's mouth but he managed to spit it out.

The electric shock collar was applied to the man's leg up to 30 times, and a white sheet was laid out on the floor, with the victim being told, "you are going to die for sure."

Pliers were used in an attempt to remove a toenail, and when this was unsuccessful, Xin inserted a sewing needle.

Extortion attempt

The man was told to tell his son that he wanted $3 million for an "investment", but during a video call the son noticed his father was being told by someone else what to say.

He checked his father's travel and found out he had come to Australia, and went to police in Sydney.

The prosecutor said police in both states went to great efforts to find the victim, with images provided by the son eventually helping an analyst find the property where he was being held.

Xin and Ge were arrested at the scene on April 25 last year, and Hawkins apprehended later.

The victim was taken to hospital suffering a stress related heart condition.

Prosecutor Nikki Conley said the offending only stopped because "police caught them in the act".

"Their motive was to get rich," she said.

The men will be sentenced in December.