Foreigners working as telephone con-artists were being held at two 'slave' properties in an alleged plot to swindle wealthy Chinese nationals out of their life savings.

Nestled in the suburban streets of inner Brisbane, more than 50 Taiwanese nationals were allegedly found crammed into locked-up bedrooms and working in an illegal call centre at the multi-million dollar homes, Brisbane Times reported.

They allegedly worked 12 hours a day, had their passports and phones confiscated, forced to shower at the same time and told it was 'impossible' to leave the Morningside and South Brisbane abodes.

A five-bedroom property listed on the market for $3 million was once an alleged slave home to up to 50 Taiwanese nationals who were allegedly forced to work in a call centre 12 hours a day in a scam operation

The Morningside property, which has been listed on the market for $3 million, was converted into an alleged slave home for foreigners to work as telephone con-artists in a plot to swindle wealthy Chinese nationals

The five-bedroom property - which comes complete with a backyard swimming pool, polished floors, four fireplaces, spa and billiards room - was sold in February for a staggering $2.65 million

The 'slavery' properties were tipped off after one of the alleged victims managed to escape and flag down motorists for help in the early hours of August 9, 2015.

'Wallet, phone, ID, passport, taken. Share house. Other people, about 20 of me. Locked doors, run away,' he said to two women, according to the publication.

The alleged victim told police he was allegedly abused and forced to stand in the middle of the room for five hours after he asked to leave the house.

Police raided the $3 million property - dubbed the 'largest known house in Morningside' - which sits on a sizeable 700-square metre of land.

Beyond the gates of the stunning five-bedroom estate, the home boasts an 'in ground suspended pool from the second floor', tennis court, a sauna, a gym room, intercom, media room and a three car lock-up garage.

They allegedly worked long hours unpaid, had their passports and phones confiscated, forced to shower at the same time and told it was 'impossible' to leave the Morningside property

The Taiwanese nationals allegedly worked long hours unpaid and were forced to shower at the same time

Police raided the multi-million dollar home after an alleged victim escaped and flagged down motorists for help

Investigators also uncovered an alleged slave house on Dorchester Street in South Brisbane where 35 Taiwanese nationals were found working inside.

The five-bedroom property - which comes complete with a backyard swimming pool, polished floors, four fireplaces, spa and billiards room - was sold in February for a staggering $2.65 million.

Yu-Hao Huang and Bo-Syun Chen have been remanded in custody on charges of conducting a business involving servitude, according to the publication.

Wu-nan 'William' Chen allegedly picked up Taiwanese foreigners from Brisbane Airport and dropped them at one of the two houses and Sheng-Jiun "Katsu" Huang was an associate.

Prosecutors alleged the slave operation was run by a 'transnational Taiwanese organised crime syndicate', with four men awaiting further hearings.

The operations were shut down last year and two properties were listed on the market.