Police are to work with officers in Vanuatu, Malaysia and China to get to the bottom of the Ufun Ponzi scam.
National police chief Somyot Pumpunmuang said another special investigation team will be set up to handle foreign cooperation on the case, since victims have been duped in all three countries.
The team will report daily to Prime Minister Prayut Chan-o-cha, who has instructed officials to investigate the case without fear of any influential figures behind the network.
Police last week searched UDBP Management (Thailand) Co and arrested its president Kevin Lai and vice-president Yang Yuan Zhao as well as seven Chinese accomplices.
Money from Ufun victims was allegedly transferred to UDBP, then sent to Malaysia and Vanuatu through foreign firms. UDBP bosses cited important figures to legitimise their scam, Pol Gen Somyot said.
Assistant police chief Suwira Songmetta said 8,706 Ufun members transferred about 30,000 baht each to UDBP, leading to losses of more than 300 million baht.
Mr Lai, a 49-year-old Malaysian, and Mr Yang, a 48-year-old Chinese national, both deny fraud charges. Investigators opposed bail for the suspects since they could tamper with evidence or threaten employees.
Ufun was granted permission to sell herbal drinks, fruit drinks and cosmetics last year but police later found it was operating a pyramid scheme to bring in new members rather than sell products.