Only three wealthy foreign investors have applied for residency since the government overhauled the rules last spring and they are in limbo.
Immigration said their applications were still being processed, and this could take months.
The Active Investor Plus visa replaced two investor visa categories in September, which has the option of investing $5 million in a New Zealand company, $7.5m in funds or $15m in listed equities and philanthropy.
But those hoping to gain residency as an investor do not yet know what investments are deemed suitable for the visa category.
New Zealand Trade and Enterprise (NZTE), which was marketing the new visa, said a list of acceptable investments should be ready early this year.
A spokesperson said NZTE had been working alongside Immigration and Ministry of Business, Innovation and Employment on technical amendments to the criteria, to ensure they were in line with the intent of the policy, and that had taken time get right.
They said it was not holding up applications from being approved.
"An investor migrant, whose application has been approved in principle, has six months (plus another six months on request) to make a minimum initial investment and invest the remainder of their funds into holding investments or other acceptable investments," the spokesperson said.
The agency is also in the process of appointing an advisory panel which will make recommendations on which managed funds or direct investments quality as an acceptable investment.
NZTE said the panel would have their first meeting early this year.
"Advisory panel members will be chosen for their relevant experience and expertise, as well as their mix of complementary skills."
Queen City Law director Marcus Beveridge, who has worked with wealthy foreign investors for 30 years, said the uncertainty over investment options was frustrating and the number of inquiries had dwindled.
"There's been a huge drop off in application numbers and interest. At the moment New Zealand is not seen as flavour of the month at all," Beveridge said.
"Business immigration has gone from a reasonable flow to a mere trickle and the policy settings are not very attractive at the moment."
He had three people interested in applying for residency under the new investor visa category but said the lack of certainty over investment options was off-putting.
"We've probably gone from one end of the spectrum to the other, a bit too far, in terms of active [investment], and without having the basics there, without having NZTE ready to actually provide the assessments ... it's a bit Mickey Mouse," Beveridge said.
The global economy meant investors may be wary of putting money in a New Zealand start-up, he said.
"I think we're kidding ourselves a bit in terms of New Zealand popularity and how many billionaires are willing to come to Aotearoa, and on top of all of that how many are actually willing to inject $5 million into a New Zealand company without probably being that familiar with New Zealand."
It was good the visa was targeting active investors, he said, but believed Australia's policy was more attractive and less risky.
Immigration general manager, border and visa operations Nicola Hogg said processing investor visa applications could take some time depending on the complexity of the applications.
"It is not unusual for residence applications to take a matter of months," she said.
The Active Investor Plus visa has a slightly different process to other visas because NZTE determines what is an acceptable investment for applicants.
"Immigration New Zealand is responsible for making final decisions on granting visas and assessing whether investors meet the conditions of their visa and ensure all nominated funds and transactions are legitimate," Hogg said.
"Active Investor Plus residence applications are complex and have a dedicated team of business immigration specialists who work closely with the applicants and their advisors throughout the process."
Announcing the new visa category in July last year, Economic Development Minister Stuart Nash said the old visa categories had attracted more than $12 billion over the past decade but much of it was passive investment in shares and bonds.
He said the new Active Investor Plus visa would attract "active and high-value migrants" who could offer their international expertise to local businesses.
The Green Party said the scheme was allowing wealthy individuals to "purchase" residency while entrenching a system that kept low-waged workers on a precarious and temporary status.