Advisers who recommended clients invest in what police have branded a Ponzi scheme guaranteeing a 5 per cent return each month are facing legal action.
Law firm FS Legal has already been instructed by one adviser's client for a claim of £2m.
But it has said investors lost an alleged £50m by putting cash in the scheme and warned time is running out for those seeking to make a claim.
Kit Sorrell, a partner at FS Legal, said people were advised to put money into the scheme by accountants and financial advisers.
He said: "It is very important to stress the time sensitive nature of these potential claims.
"There is a period of six years from the date that the money was paid over by which a claim has to be brought to court.
"If it is not brought to court in that time then the claim just lapses. No matter how good the claim is, there is no prospect of getting any recourse with the client.
"Given the date of some investments, time to claim is now running short."
The investment scheme was run by CMW FX, which was dissolved in 2015 after the arrests of 15 people at its offices in London.
In 2016 the City of London Police revealed it had been investigating the company over the fund, which offered 5 per cent interest a month but, officers said, investors saw "little or no returns" and it was branded a Ponzi scheme.
Mr Sorrell said: "At this stage we welcome instructions from other investors and are dealing with matters on a no-win no-fee basis.
"Financial advisers tend to have a fairly limited pot of insurance that will respond to and pay out these kinds of claims.
"The pot is distributed on a first come first serve basis so if the financial adviser has a pot of insurance of say £1.5m and has a number of investors that have put into the scheme then it is quite conceivable that the first three or four might exhaust that fund.
"And if you happen to be number four or number five then you are not going to get paid. For all those reasons it is very important to think about taking action on these claims as soon as possible."
A spokesman for the City of London Police said: "The City of London Police is currently awaiting charging advice from the Crown Prosecution Service for 12 individuals who are under investigation in this case."