About 3000 foreign trusts have told Inland Revenue they want to register under new rules that require them to reveal financial information and their ultimate owners.
That is almost 9000 fewer than the 11,750 which existed before the Panama Papers scandal erupted.
New Zealand's foreign trust industry came under the spotlight last year in the wake of the Panama Papers - a cache of 11.5 million documents leaked from Panamanian law firm Mossack Fonseca.
Labour spokesman for Revenue, Michael Wood, said the fact that so many trusts exited showed the need for a transparent, searchable register.
"It's no surprise that the 12,000 foreign trusts registered in New Zealand has wilted to around 3000 after IRD's deadline for more information has passed," Wood said.