TORONTO (Reuters) - Canada's main stock index fell on Tuesday, hurt by weakness in resource stocks and a tumble in shares of Valeant Pharmaceuticals International Inc (>> Valeant Pharmaceuticals Intl Inc) as the market reopened following an extended Christmas break.

The market, which was closed Friday for Christmas and Monday in lieu of Boxing Day on Saturday, rose 2.2 percent last week.

"It's off of low volumes, but the Canadian market is just effectively playing catch-up to the U.S. market," said Ben Jang, portfolio manager at Nicola Wealth Management.

The materials group fell 2.7 percent following weakness in U.S. materials stocks on Monday.

Goldcorp Inc (>> Goldcorp Inc.) fell 3.9 percent to C$16.23, while Barrick Gold Corp (>> Barrick Gold Corp.) was down 3.3 percent at C$10.49 and Potash Corporation of Saskatchewan Inc (>> Potash Corporation of Saskatchewan Inc) declined 2.4 percent to C$24.50.

Valeant Pharmaceuticals International Inc (>> Valeant Pharmaceuticals Intl Inc) fell 11.1 percent to C$140.19 following news on Monday that its chief executive officer, Michael Pearson, is taking medical leave.

"He is still the main driver in the company and I think the market has realized that," said Jang.

The stock saw a more moderate loss in New York after falling sharply on Monday (>> Valeant Pharmaceuticals Intl Inc).

The Toronto Stock Exchange's S&P/TSX composite index <.GSPTSE> closed down 64.05 points, or 0.48 percent, at 13,245.75, with five of the index's 10 main groups in negative territory.

Energy stocks fell 0.7 percent, including a 1.2 percent drop in Suncor Energy Inc (>> Suncor Energy Inc.) to C$36.46.

Crude oil prices rallied as colder weather prompted buying a day after prices slid 3 percent, but slowing global demand and abundant supplies from OPEC members were expected to remain a headwind.

Financial sector stocks rose 0.5 percent, helped by a 1.0 percent advance for Bank of Montreal (>> Bank of Montreal) to C$79.51.

BCE Inc (>> BCE Inc.) rose 1.4 percent to C$54.77, while Loblaw Companies Ltd (>> Loblaw Companies Limited) was up 1.7 percent at C$67.00.

(Reporting by Fergal Smith; Editing by Bernadette Baum and Leslie Adler)

By Fergal Smith