Police said three more men have been arrested for suspected conspiracy to defraud in relation to the unlicensed cryptocurrency exchange JPEX, bringing the total number of arrests to 11.
More than 2,000 people have now reported a loss of over HK$1.3 billion on the platform.
Sources said the police have asked telecom operators to block the JPEX website.
Meanwhile, the Securities and Futures Commission issued a statement rejecting claims by JPEX that it had sought guidance from the regulator in the hope of complying with legal requirements, but had received no positive response.
The SFC said it had made enquiries about what it called JPEX's misrepresentations and unlicensed activities, but the platform had been uncooperative.
It said there hadn't been any communication between the SFC and JPEX on licensing-related matters.
"The SFC affirms that JPEX has never approached the SFC in respect of any potential licence application, and that no entity in the JPEX group is licensed by the SFC or has applied to the SFC for a licence to operate a virtual asset trading platform in Hong Kong. As such, there has been no communication between the SFC and JPEX on licensing-related matters," the statement says.
"Subsequent information obtained has led to suspicion of fraud and the SFC has referred the matter to the Police. As investigations are ongoing, the SFC cannot make any further comment."