Britain's Global Witness organisation says that New Zealand shell companies crop up regularly as a means of international money-laundering.
Some of these companies have been linked to a $NZ1.5 billion money-laundering scandal in Kyrgyzstan involving the Asia Universal Bank, which is now insolvent.
It's believed some of the money may have embezzled by former President Kurm anbek Bakiyev and his family.
Global Witness says that New Zealand shell companies are attractive to international criminals because New Zealand is a developed, reputable country and no checks are required on who the real owner is, or what the company is doing.
It says there should be rules against agents who are employed legally to act as proxy shareholders or directors in the shell companies.
In May, the European Union said New Zealand does not have strong enough controls against money laundering.
But commercial lawyer Stephen Franks says that more regulations is not the way to stop fraudsters from using New Zealand to launder money.
The solution is, as usual, to enforce the law that you've got, he says. Put the money into chasing crooks.
Make sure that it is a very unprofitable experience to be operating as a crook from New Zealand.
We're not doing that.
If these agents sign false returns or don't comply with companies law, they should be hounded, Mr Franks says.