Molson Coors Brewing Co reported a lower-than-expected quarterly profit on Tuesday mainly on weak volumes across all markets, prompting the beer maker to issue a tepid volume forecast for 2010.

The brewer of Coors Light and Molson Canadian was also weighed down by cost inflation in the United States and Britain.

Overall consumer demand remains sluggish, and we see these conditions continuing to impact volume and mix in the near term, Peter Swinburn, Molson Coors president and chief executive officer said.

Looking to 2010, we expect volume to remain challenging, especially in the first half, Swinburn added.

Beer's relatively low price has made it somewhat resilient in the global downturn. But promotions by some wine and spirits brands, as well as price increases on some beers to cover rising commodity costs, has heightened competition.

In the latest fourth quarter, Molson Coors earned $222.1 million, or $1.19 a share, compared with $93.7 million, or 51 cents a share, a year earlier.

Excluding items, profit was $1.02 a share, missing analysts' average forecast of $1.10, according to Thomson Reuters I/B/E/S.

Sales excluding excise taxes rose 11 percent to $820.8 million. Worldwide beer volume declined 4 percent as consumers remained cautious in the weak economy.

Earlier on Tuesday, MillerCoors, the combined U.S. operations of Molson and SABMiller PLC , reported a 21.6 percent slide in fourth-quarter net income reflecting a tough economy and a sharp rise in share-based salary bonus packages.

It's tough out there, and we saw the effect of ongoing economic pressure and unemployment on beer sales, especially in the fourth quarter, MillerCoors CEO Leo Kiely said in a statement.

(Reporting by Dhanya Skariachan; Additional reporting by Martinne Geller, editing by John Wallace, Dave Zimmerman)