Labour is questioning whether new legislation to prevent money laundering is too wide.
The Government plans to introduce a bill that cracks down on money laundering, identity crime and trafficking later this year.
Initial changes targeting money laundering will come into effect at the end of this month.
Banks will be required to report to the police all international transfers of more than $1000 and all physical cash transactions of more than $10,000.
But Labour's justice spokesperson Andrew Little questions whether the $1000 threshold is too low.
If it catches a lot of innocent people, he said the job of catching genuine money launderers will be much harder because of the volume of transactions to examine.