In a press release published yesterday, Commerce Minister Simon Power stated that the FMA will "enforce securities, financial reporting, and company law as they apply to financial services and securities markets. It will also regulate and oversee, trustees, auditors, financial advisers and financial service providers including people who offer investments". The Reserve Bank will retain responsibility for prudential regulation.
The Government's intention is that legislation establishing the FMA will be passed this year and that the FMA will begin operating early in 2011. For further information see here (and, in respect of auditor oversight, here).