They raided the offices of Barry Kloogh who is the chief executive officer of financial advice company Breathe Financial.
The action followed enquiries by the FMA, leading to a referral to the SFO, a joint statement from the agencies said.
The authority would be assessing any matters relating to the Financial Advisers Act and supporting the SFO investigation.
They asked anyone with information they consider might be relevant to this investigation to contact the SFO either by phone: 0800 109 800 or email: firstname.lastname@example.org.
The authority was working to secure and preserve client funds, it said.
It appears from the Breathe website that the company's main activity was mortgage advice and helping clients repay their loans faster. Kloogh is credited as being the creator of the DebtBreaker System, an at-home software program designed to help people get out of debt and boost savings.
TMMOnline understand Kloogh was previously with NZ Home Loans.