Consumer confidence in the metropolitan area dipped last month because of concern about grocery prices and possible tax increases in 2013, according to a poll released Thursday.

The decline coincided with the end of the holiday shopping season, a crucial period for many retailers.

The Siena College Research Institute Thursday reported its confidence index for Long Island, New York City and its northern suburbs was 81.3 points in December, down 1.8 from the previous month. In November, the index hit a five-year high of 83.1 points despite the damage wrought by superstorm Sandy on Oct. 29.

Readings of 76 or higher indicate the number of people who are optimistic about their immediate financial future exceeds those who are pessimistic.

Although their confidence dipped from the prior month, metro-area residents were more bullish in December about their immediate economic future than counterparts in New York State and the nation. It's a trend seen in much of 2012.

"The New York City area tends to have a stronger, more diversified and robust economy than the rest of New York State and other parts of the country, especially right now," said Siena pollster Donald Levy. "Confidence levels have been higher there consistently."

advertisement | advertise on newsday

In December, Siena's statewide index was 77.3, compared to the metro area's 81.3.

Levy said metro-area residents told Siena last month they were worried that partisan gridlock in Washington over the "fiscal cliff" would result in higher income taxes.

They also were watching food prices. The number of area residents saying the cost of groceries was either somewhat or a very serious problem rose 6 percentage points in December to 67 percent from November's 61 percent.

At the Westfield Sunrise mall in Massapequa Thursday, shoppers complained about higher prices for staples such as milk, beef and fruit.

"Gas prices seem to have come down a bit, but I'm definitely paying more for food," said Liz Rocco, a retiree from Amityville. "You never seem to get a break. One thing goes down, but others go up . . . I find it hard to make ends meet."