As of Tuesday, silver Eagle sales for the month totaled 7.1 million ounces, data from the U.S. Mint's website showed, surpassing its previous record of 6.1 million ounces set in January 2012.

"Not only do we have clients calling in; they are buying in huge quantities," said David Beahm, vice president of Blanchard & Co, a New Orleans-based retail coin dealer.

"They are buying the entire 500-ounce boxes that are sealed by the U.S. Mint, that's what people want right now," said Beahm, referring to the standard sealed silver Eagle "monster" box containing 500 one-ounce coins the Mint sells only to its handful of authorized wholesalers.

Earlier this week, the Mint resumed supplying silver Eagles after it halted sales on Jan. 17 as soaring demand depleted its stock.

However, silver coin sales to dealers are still through the allocation process, or rationing, a U.S. Mint spokesman said on Tuesday.

With two more days remaining in January, gold coin sales were 140,000 ounces, compared with 127,000 ounces for all of January 2012. Sales appear set for the highest monthly tally since July 2010.

U.S. gold and silver coin sales have been exceptionally strong in January, building on a late 2012 rally as collectors scramble to snap up newly minted 2013 coins and investors seek refuge from U.S. economic uncertainty.

Some coin dealers, however, warn of a post-January drop in sales similar to last year's pattern, as early interest tends to wane once the first mintage is over.