The Serious Fraud Office has confirmed it is investigating a US-based loan provider tied up with the B'On pyramid scheme and another SFO prosecution.
After an initial probe the SFO on Thursday said there was "reason to suspect that an investigation may disclose serious or complex fraud" involving the Brockstar Group.
Brockstar is headed by the Californian couple of self-styled "Sir" Brian Willis and his partner "supermodel" Snizhana Willis.
Acting SFO chief executive Simon McArley said the agency was alerted to Brockstar during investigations into B'On Financial Services and Derivatek.
Last month, B'on Financial Services director Jacqui Bradley was sentenced to seven years and five months' jail after being found guilty of 71 counts of fraud.
The SFO has also charged Derivatek's Gregory Arnott with theft and making false statements.
In both cases substantial sums - reported to be US$1.3 million each time - had been paid as advanced fees in an attempt to secure loans worth as much as $20m from Brockstar but no loans eventuated and the fees were not returned.
Mr McArley cautioned that the conduct may not have occurred in New Zealand, and would be outside the New Zealand jurisdiction.
"However at the very least we can raise the matter with the US and other overseas agencies with whom we have ties, and see if they are in a position to initiate some action."
Earlier this month, Fairfax reported B'On and Derivatek each paid US$1.3m to Brockstar on the promise of loan packages exceeding $20m.
Willis had been the subject of numerous complaints by investors and an Orange County Superior Court judge had described Brockstar's loan business as "a classic con game".
Willis said he was appealing the judgment.