MANCHESTER, N.H. -- Republican presidential candidate Rudy Giuliani has lost ground and rival Mitt Romney has established a lead in New Hampshire, according to a new poll.

Full Results: Primary Poll

The two were statistically tied for first place two months ago.

The WMUR-CNN poll of likely Republican voters conducted by the University of New Hampshire shows Romney with 33 percent support, up from 25 percent in the same poll in September. Giuliani has declined, slipping to 16 percent compared to 24 percent in September.

A similar poll of Democratic contenders is due later Tuesday.

Those polled also described Romney as the most likely to win the nomination, with 39 percent choosing him and 26 percent saying Giuliani could go the distance.

Just 8 percent said John McCain has what it takes to win the nomination, but 18 percent of voters said they would vote for him, the same as in September. Although his support has remained steady, McCain has moved into second place because of Giuliani's slide.

"The Romney campaign and the McCain campaign have been here a lot more, doing more events than the Giuliani people," said Andy Smith of the UNH Survey Center. "Both Romney and McCain have been on TV awhile. Rudy Guiliani has just gone on the air with his commercials."

Smith said that according to the poll, the most important issues to Republican New Hampshire voters are Iraq, illegal immigration and the economy. More respondents said that McCain would best handle Iraq, while Romney was the choice for illegal immigration and the economy.

"Romney's ads have really been good at pushing traditional Republican positions like low taxes, good management of government, good economy," Smith said.

Coming in fourth for the first time was Ron Paul, who has seen a surge of interest, partially sparked by a one-day online fundraising record of $4.2 million. He was the choice of 8 percent of likely Republican voters, up from 4 percent in September.

Despite the uptick in support and fundraising surge, Paul remains the least popular of the candidates, with 61 percent saying they would not choose him under any circumstances.

Fred Thompson saw a significant slide to 4 percent from 13 percent in September. Thompson had consistently polled in double digits before he entered the race.

Mike Huckabee saw a slight increase to 5 percent from 3 percent in September. Smith said his socially conservative platform hasn't caught on with New Hampshire voters, who placed social issues far down the list of important issues.

Although Romney has a strong lead on the other candidates, only 14 percent of those surveyed said they know for sure who they're supporting. Another 29 percent said they were leaning toward a candidate and 57 percent said they had no idea who they would choose.

Smith said that softness in support means Giuliani can still contend for New Hampshire.

"Certainly, Guiliani has much better numbers than McCain does, more fame, more celebrity than McCain does nationwide," he said.

The date of the New Hampshire primary is still not set. Smith said that with so many states scheduling their primaries, candidates may put more emphasis on the earliest states because they don't have much time to recover from a loss.