Gold has joined the list of global assets and indexes under review by the U.K. financial regulator, according to a media report.
The U.K. Financial Conduct Authority (FCA) has begun a preliminary look at the benchmark rate for the precious metal, according to a report by Bloomberg news agency, who quoted a source familiar with the situation. This forms part of a wider scrutiny by officials to find out how global benchmarks are set.
The source didn't disclose which gold benchmarks were part of the probe and, when contacted by CNBC, the FCA declined to comment.
(Read More: Banks brace for billion-dollar forex probe)
Regulatory bodies across the world have already formally launched an investigation into the alleged manipulation of foreign exchange rates in October. Several banks have publicly stated that they are complying with officials and have launched internal investigations while some lenders have suspended staff.
This comes after the last year's probe into the London interbank offered rate (Libor), which is used to price over $300 trillion of financial contracts around the world. Several banks have since received heavy fines for their role in the scandal.
One of the most important of the various gold benchmarks is the London Gold Fix. This occurs twice daily and consists of gold dealers from London's five biggest bullion banks -- Societe Generale, Barclays, Deutsche Bank, HSBC and Scotiabank -- creating a common price for a large amount of purchase and sale orders.
When contacted by CNBC, representatives from the five banks either declined to comment or were not immediately available for comment. There was no mention in the Bloomberg report that any of the five bullion banks were involved in the preliminary investigation.
(Read More: Biggest banks face forex probe questions)
The price set at the London Gold Fix is used by refineries and mining companies to value their inventories, as well as the Bank of England. Smaller coin dealers and gold jewelry manufacturers also use benchmark and it's also used by gold derivative markets to put a price on gold derivatives such as futures, swaps and options.
In July last year, Ned Naylor-Leyland, a director at investment management firm Cheviot, told CNBC that he suspected that Gold may have been manipulated like the London interbank rate or Libor over a long time frame.
(Read more: EU to fine banks billions of euros over rate rigging)
"A number of the big commercial banks have very large short positions which they like to manage and make easy money from," he told CNBC.
Martin Arnold, a senior analyst at ETF Securities told CNBC that after the LIBOR scandal, regulators are likely to step up their investigations in order to engender confidence in the transparency of price discovery.
"Gold is one of the most liquid markets and the gold fixing prices set in London reflect actual trades at two set times of the day, rather than just a theoretical surveyed price as is the case in some interest rate markets, he told CNBC via an email.
"While there is potential manipulation in any market, I think the market depth and traded price setting means it is unlikely that gold prices are being manipulated. For physically backed ETPs (exchange-traded products), investors can see the current spot prices in real time and pricing is not dependent on the fixing prices, so there is complete transparency for the end gold investor."
By CNBC.com's Matt Clinch. Follow him on Twitter @mattclinch81