Updated: 12:28 p.m.

State Assemblywoman Dede Scozzafava (R) begins the sprint to the Nov. 3 upstate New York special election with a 35 percent to 28 percent lead over attorney Bill Owens (D), according to a poll released Thursday.

Conservative Party nominee Doug Hoffman, who is airing TV ads and is expected to be a factor in the race, garnered 16 percent in the Siena Research Institute poll of likely voters.

Siena pollster Steven Greenberg said the survey shows that the eventual winner of the three-way race to succeed former Rep. John McHugh (R) will likely capture only a plurality of votes cast and not a majority.

“This is a wide open race. One in five voters is currently undecided,— Greenberg said in a statement. “Add to that the fact that one-third of Scozzafava’s current supporters and one-quarter of Owens’s current supporters say they are not very certain of their choice and that they very well may change their minds between now and Election Day.—

The poll found that the economy and health care are the two most important issues that voters want their Representative working on in Washington. It also found Scozzafava ahead in the northern portion of the sprawling district while Owens led in the central counties. The two candidates were virtually tied in the eastern part of the district.

Not surprisingly, the poll showed that the state Assemblywoman is the best-known candidate in the race since she is the only current officeholder. The survey found that Scozzafava had a 33 percent favorable/20 percent unfavorable rating, while 47 percent of those polled had no opinion. Owens had a 23 percent favorable/12 percent unfavorable rating, with 64 percent undecided.

The poll of 622 likely voters was conducted Sept. 27-29 and had a margin of error of 4 points.

In a related development, the Club for Growth, the national anti-tax group that has endorsed Hoffman, began airing $250,000 worth of TV and radio ads in the district Thursday.

The 30-second TV ad, called “Four of a Kind,— does not make reference to Hoffman at all, but a narrator asks “who’s more liberal, Dede Scozzafava or Bill Owens?— and compares the two to Speaker Nancy Pelosi (D-Calif.) and unpopular New York Gov. David Paterson (D).

“Scozzafava or Owens, that’s like asking Paterson or Pelosi,— the narrator says at the end of the ad.

The radio spot, meanwhile, is a direct attack on Scozzafava, who it calls “a liberal in disguise … so liberal she’d be Nancy Pelosi’s favorite Republican.—

“Fortunately, upstate Republicans have a choice,— the voice-over continues, calling Hoffman “a principled Republican running on the conservative line.—

Beyond interest groups such as the Club for Growth, both parties are expected to spend heavily on the race. The 23rd district only marginally favors Republicans.

As of Thursday morning, the Democratic Congressional Campaign Committee had spent about $127,000 in independent expenditures on the race while the National Republican Congressional Committee had spend $119,000.

McHugh resigned to become Army secretary, and Gov. David Paterson (D) set the special election to coincide with Election Day, Nov. 3.