Jim Wilson/The New York Times

MANCHESTER, N.H. — While Mitt Romney remains the front-runner among Republican primary voters in New Hampshire, his once formidable lead appears to be slipping.

From New Hampshire Reporting on the candidates and voters from the Granite State.

In the latest release of the 7 News/Suffolk University tracking poll of likely voters in the New Hampshire Republican primary, 33 percent said they planned to vote for or leaned toward Mr. Romney, the former governor of Massachusetts. In the last poll, released Wednesday, Mr. Romney was the choice of 43 percent, and his support has been steadily decreasing since then.

Ron Paul remains in second place, backed by 20 percent. Jon M. Huntsman Jr., with 13 percent, and Newt Gingrich, 11 percent, were essentially tied for third place. Mr. Huntsman, a former governor of Utah, was backed by only 7 percent in last week’s poll. .

With little time for the candidates to still make their case, 12 percent of the voters surveyed remain undecided. And an additional 24 percent say it is possible that they will change their minds before casting their vote on Tuesday.

But one note of caution should be added to the mix. Pre-primary polls can be off, sometimes by a lot. For example, in 2008, the polls showed Barack Obama with a solid lead in the Democratic New Hampshire primary after winning the Iowa caucuses, but Hillary Rodham Clinton took the state.

The statewide survey was conducted Saturday and Sunday with 500 likely voters in the New Hampshire Republican presidential primary. The poll of landlines and cellphones has a margin of sampling error of plus or minus four percentage points.