More New Zealand investors have come forward fearing they have been caught up in suspected global investment scam.

The Herald reported earlier this month that authorities are looking into the apparently sophisticated ruse that has allegedly duped Kiwis out of their life savings.

Manfred Bredl, 63, plunged $525,000 into what he thought was a ground-breaking carbon emissions scheme, reportedly backed by the Mexican government.

But Bredl believed he, and three other New Zealanders that he knew of, had been duped by individuals behind two dummy companies – FM Wealth Management Ltd, purportedly based in the Cayman Islands, and private share company Eco-Plant Corporation.

Since the Herald reported his case on June 19, others have spoken out about dealings with the charismatic, smooth-talking operators behind what's alleged to be a sophisticated con.

One Kiwi investor claims FM Wealth Management conned about $85,000 out of him during 12 months of interactions with the "brilliant, highly- knowledgeable" and "smooth, confident talker" man known only as "Bruce Matthews".

Paul Mackenzie avoided the suspected trap, wary of get-rich schemes.

He said FM Wealth Management approached him recently about a new company merger to release a medicinal marijuana product.

A British-sounding man "hounded" him for weeks, Mackenzie said, with promises to send out portfolios.

While Mackenzie thought their websites checked out, he blew them off saying he wasn't interested in quick rich schemes "as I am aware of the many pitfalls".

One Bay of Plenty retiree wasn't so lucky and got sucked in.

He invested NZ$60,000 after being cold-called by a "Bruce Matthews" reportedly calling on behalf of FM Wealth Management.

"My story is almost word for word with what you printed about Mr Bredl," the 74-year-old who wanted to remain anonymous told the Herald.

"My wife and I thought he was absolutely genuine until your article in the Herald came up. [His wife] read it that morning and just said, 'S***, look at this'. I just couldn't believe it."

After being lured to invest US$5000 into a supposed leukaemia cure company, the man lumped more into Eco-Plant shares, wired to a Mexican bank account.

He was expected a $200,000 windfall this month (July). But he's "written off" his money.

"It's a very big loss. We're retired and this was a good part of our nest egg. It's going to make things very tight for us over the next few years," said the man, who now wants to file a complaint with police.

New Zealand Police refuse to confirm whether they are investigating FM Wealth Management.

The Cayman Islands Monetary Authority has blacklisted FM Wealth Management and, in December, New Zealand's Financial Markets Authority (FMA) issued a warning for Kiwi investors to steer clear of the company.

The companies, which reportedly have offices in Cayman Islands, Toronto, and Buenos Aires, have not responded to phone calls or emails from the Herald.

A Herald investigations earlier this month revealed that Kiwis were losing up to $500 million annually to international scammers and the number of reported incidents had risen sharply this year.

Bronwyn Groot, fraud education manager at the Commission for Financial Capability, said Kiwis need to be wary of cold callers.

"Almost every day, people contact me saying they have lost money through investments scams and sadly, $500,000 is small," she said.

Internet safety group Netsafe said New Zealanders should be "extremely wary of any unexpected investment offers" and always deal with companies that are authorised to operate in New Zealand.