The Serious Fraud Office is considering a whistleblower scheme that pays informants who come forward about suspected fraud.
The SFO says that in the past 18 months prosecutors have dealt with seven actual or alleged Ponzi schemes, whereby investors' money is used to produce false returns for other investors.
Acting director Simon McArley says the combined loss of most of those cases adds up to $400 million.
He says a reward programme similar to that in the United States, which rewards informants by up to 30% of a financial penalty of $1 million or more, is being considered.
He says it could help tackle white-collar crime similar to the alleged offending at Aorangi Securities and Ross Asset Management.
Mr McArley says several options are being discussed among agencies including the Ministry of Justice, Inland Revenue and the Department of Internal Affairs.