The changes in Riyadh's reserves were revealed by the World Gold Council, the industry-backed body that regularly tracks official bullion holdings.

According to the WGC, the Saudi Arabian Monetary Agency, the central bank, has gold reserves of 322.9 tonnes, more than double the 143 tonnes it had previously reported.

The central bank said in a footnote to its latest quarterly report that "gold data have been modified from first quarter 2008 as a result of the adjustment of the Sama's gold accounts".

Sama did not respond yesterday to calls seeking further comment.

Analysts said the rise in official gold holdings probably represented an accounting shift rather than fresh purchases.

One possibility is that a large fraction of the country's gold was not considered until now part of the official reserves. The fact that Riyadh retroactively updated its gold reserves since 2008 would support this theory. But, without an official explanation, analysts were keeping their options open.

At current prices the extra gold now declared to be in Saudi Arabia's official reserves amounts to $7bn (€5.6bn, £4.7bn).

David Fuller's view Creditor nations are very unlikely to sell any of their central banks' gold bullion reserves but they might increase them as we have seen with China, India and Russia over the last year.

From and investment perspective, I continue to regard gold bullion (inflation adjusted, monthly, weekly & daily) as an attractive long-term investment, best accumulated following setbacks. On a short-term basis I am cautious following gold's key day reversal yesterday. A new closing high is now required to offset the near-term possibility of some additional reaction and to reaffirm the uptrend.