Police have smashed seven illegal money-lending and money-laundering companies and agencies that were charging interest rates as high as 1,396 per cent - 23 times the legal limit.
In a new trick to lure borrowers, some of the loan sharks were offering second mortgages, investigators said.
In a series of raids in five areas on Monday afternoon, officers with search warrants arrested 34 people - 24 men and 10 women, aged 18 to 64 - including two with triad backgrounds.
More than 1,500 loan applications and borrowers' records dating from October to December this year were found, involving more than HK$25 million.
"The police believe that the agencies worked with money lenders to charge exorbitant rates to borrowers in the guise of administrative or consultancy fees," Chief Inspector Neil Whyte of the New Territories North regional crime unit said.
Police also found a syndicate operating intermediary agencies from cold-calling centres in the New Territories - a tactic to make them harder to trace than lenders advertising loans in other ways, Whyte said.
Borrowers were charged interest rates of 400 per cent to 1,396 per cent, but the loans were small, typically ranging from HK$1,000 to HK$15,000, he said.
The seven companies - six intermediary agencies and one unlicensed loan company - were found to have connections with more than a dozen licensed money-lending companies.
Superintendent Lau Shu-sing, of the organised crime and triad bureau, said police would investigate the involvement of the licensed companies.
Officers confiscated equipment such as computers and retractable banner stands, as well as bank documents including bank books and bank cards.
"The crime syndicates are also involved in laundering more than HK$30 million through 20-odd bank accounts in the span of two years," Lau said.
He warned the public to borrow only from lending companies with licence numbers.
Anyone in doubt should contact police immediately, he said.
The suspects were arrested for illegal money-lending, charging excessive interest and money laundering. As of last night, no one had been charged.