The Financial Markets Authority is warning against a rise in investment impostor scams, where legitimate business names are used to trick people into giving up their cash.
Between April and November a third of reported investment scams had used details of real businesses to trick investors, sometimes through fake websites or social media accounts.
During the same period last year only 10 percent of investment scams were deemed impostor scams.
Director of regulation Liam Mason said the steep rise had begun since the emergence of Covid-19.
"In the past, scammers have attempted to exploit New Zealand's image as a well-regulated market but these impostor scammers seem to be more sophisticated and could be due to growth of online commerce due to Covid-19.
"There's a lot of public information available regarding the registration of New Zealand businesses, which is important for our transparency, but scammers may try to exploit this."
"The best solution is for New Zealanders to be inherently sceptical of any investment opportunity that seems too good to be true and to do a bit of background research if there are any red flags."
Mason said red flags could include the use of overseas phone numbers or contact information, the website domain not matching the content of the website, and the promise of higher returns.
"Warnings about scams and fraud have been a priority for the regulator throughout Covid-19, as consumers may be more susceptible to seeking high return investments in uncertain economic conditions."
The owner of a Christchurch private investment firm said when his company's details were used by scammers he felt "powerless".
Garry Carleton's firm, GRC Investments Limited, was exploited by scammers who created a website called GRC Trustee, using GRC Investments' business address and certificate of incorporation to fool investors.
"I was annoyed and worried when I first found out ... annoyed that investors' money could be stolen and concerned that somebody might turn up on my doorstep and threaten my family if we didn't pay what they'd lost to the scammers," Carleton said.
"Then I remembered the Companies Office has added optional fields to their website that let me add extra details about my company. I've used those to add a warning about the scam, should anybody look up my company."
He said after that the scammers' website stopped linking to his company on the Companies Office website.
The FMA said about one in five New Zealanders have been approached about an investment scam in the past, with those aged over 70 more likely to be approached.
Email was the most common form of contact, followed by social media and over the phone.