Cold calling about pensions is now banned, with firms facing fines of up to half a million pounds if they make unsolicited phones calls in the UK.
Cold-calling has been used by fraudsters trying to steal life savings or persuade people to invest in high-risk schemes. About 240 million scam calls were made last year, with an average of £91,000 stolen per pension scammer victim, the Financial Conduct Authority (FCA) found.
However, many scam phone calls originate from abroad, making it difficult for authorities to track and capture those responsible.
Alistair Wilson, Zurich's head of retail platform strategy, said consumers should not let down their guard as pension fraudsters are likely to "evolve new tactics to sidestep the ban" and as overseas calls are not covered by the clampdown it could present "a potential loophole for scammers operating from overseas".
Launching the ban, which was called for by IFA Darren Cooke of Red Circle Financial Planning, City minister John Glen has recommended all savers seek independent advice. "I'd also urge all savers to seek independent advice if you're thinking about making an important financial decision," he said.
"Pension scammers are the lowest of the low. They rob savers of their hard-earned retirement and devastate lives. We know that cold-calling is the pension scammers' main tactic, which is why we've made them illegal.
"If you receive an unwanted call from an unknown caller about your pension, get as much information you can and report it to the Information Commissioner's Office," Glen said.
Lesley Titcomb, chief executive of The Pensions Regulator, adds: "The cold-calling ban sends a very clear message - if anyone calls you about your pension, it's an attempt to steal your savings.
"The ban draws a line in the sand for scammers. Cross it and you should expect to be prosecuted."
Not all cold callers are covered under the ban, with those authorised by the FCA, or a trustee or manager of an occupational or personal pension scheme exempt.
Where the recipient of the call consents to the call, or has an existing relationship with the caller, they are also exempt from the ban.
Guy Opperman, Minister for Pensions and Financial Inclusion, said: "Pension scams are despicable crimes, fleecing people of the retirement they've earned by doing the right thing, working hard and saving for the future.
"Banning pensions cold calling will protect people from these callous crooks and ensure fraudsters feel the full force of the law."
Tom Selby, of pensions firm AJ Bell, said: "Prohibiting cold-calling is only part of the solution and will by no means eradicate the threat of scam activity altogether. Pensions remain a juicy target for fraudsters and some will inevitably look to circumvent the ban or simply ignore it altogether."
He urged anyone who received a call out of the blue about pensions to simply hang up the phone.
Kay Ingram, director of public policy at financial adviser LEBC, was one of a number of commentators who said the cold calling ban of itself would not deter determined criminals.
"Success will depend upon the public having confidence that no legitimate adviser or pension provider would approach them in this way. The government, pension providers and the regulatory bodies will need to do more to stamp out this crime," she said.