Most Americans are nowhere close to having their holiday shopping done, a new Reuters/Ipsos poll shows, raising hope there could be a big boost in sales during the last two weeks before Christmas.

The survey results could provide solace for retailers in an environment where Americans' view of the economy and their finances took a turn for the worse in early December.

Fifty-eight percent of respondents in the survey said they had done about half or less of their holiday shopping so far. Twenty-eight percent said they still had not started and 16 percent had completed less than a quarter of it, the poll found.

Only 18 percent said they had completed their shopping, which suggests that stores will be busy in the final two weekends before Christmas.

"One thing is for sure, consumers procrastinate every year and they wait until the very last week and even the few last days to go shopping," said Jharonne Martis, director of consumer research for Thomson Reuters.

The final weekend before Christmas, including Saturday, Dec. 22, "is going to be the pivotal sales weekend."

The final weekend takes on extra importance this year as Christmas falls on a Tuesday, instead of the Sunday it fell on last year. An extra two days between Thanksgiving and Christmas is also expected to boost sales in the final stretch of the November-December holiday season.

Shoppers are keeping an eye on their budgets.

Only 14 percent of respondents plan to spend more this year than in 2011, while 55 percent will spend the same and 20 percent spend less.

But that does not mean they will actually spend less.

"Expectations and what happens are really two different things," Martis said. In general, shoppers expect to spend less, and then spend more "every year, without failure."

While Black Friday and even Thanksgiving were busy this year, some of the biggest shopping days are still to come, including the two Saturdays before Christmas.

Sales at stores open at least a year, or same-store sales, are expected to be particularly strong for discount chains and department stores this month, according to Martis.

Discount retailers that release monthly data, such as Target Corp and Costco Wholesale Corp, are expected to post a 5 percent rise in same-store sales, up from 4.3 percent growth in December 2011, Martis said. For department stores, including Macy's Inc and Nordstrom Inc, a gain of 4.5 percent is forecast after a 4.2 percent rise last year.

Three percent growth in same-store sales is considered good, according to Martis. Same-store sales at apparel chains should rise just 2.3 percent versus 4 percent growth last December.

The findings are from an Ipsos poll conducted for Thomson Reuters from Dec. 8 to Dec. 11, with 1,330 American adults interviewed online.

Results are within the poll's credibility intervals, a tool used to account for statistical variation in Internet-based polling. The credibility interval was plus or minus 3.1 percentage points.

The poll is the latest in a series that Ipsos will conduct during the holiday season.