Four state Senate incumbents, including two in western New York and one in Westchester County, are maintaining sizeable leads against their opponents just days before Election Day, a Siena Poll today found.

Sen. Suzi Oppenheimer, D-Mamaroneck, Westchester County, has a whopping 35 percentage-point lead over Republican challenger, Liz Feld. The poll showed the 11-term incumbent with a 64 percent to 29 percent lead over Feld, mayor of Larchmont, down slightly from 61 percent to 24 percent lead in a Siena poll earlier this month.

“Given Oppenheimer’s advantage in favorability, the district’s large Democratic enrollment edge, and the support for (Barack) Obama within the district, Feld appears to be headed for defeat,” said Siena poll spokesman Steve Greenberg.

Updated: Feld’s spokesman William O’Reilly responded: “Are they sure they’re polling the right district? This is the 37th, home of the highest property taxes and lowest state school aid in America. Everyone we talk to is fed up and ready to make a change.”

Sen. Joseph Robach, R-Greece, Monroe County, has expanded his lead against Democrat Richard Dollinger to 52 percent to 39 percent, edging up from an 11-percentage-point advantage last month, Siena found.

Robach, a former Democrat, is holding his lead despite major investment by Democrats into Dollinger, who held the seat before Robach, in a heavily Democratic district. The Siena poll shows Democratic presidential candidate Barack Obama with a 29 percentage-point lead over Republican candidate John McCain in the district, which includes most of the city of Rochester.

“Senator Robach has strong support among Republicans and independent voters, as well as the support of more than one-third of Democrats,” Greenberg said. “He enters the final week of the campaign in a strong position.”

The Albany-based Siena has been polling the most competitive state Senate races in recent weeks as Republicans seek to maintain their slim majority. With a 31-29 seat majority, Republicans have been trying to fend off challenges from Democrats in races across the state, likely making the campaigns the most expensive in state history.

The college expects to release another set of polls on other tightly contested races over the weekend. Election Day is Tuesday.

Siena today also polled the re-election bid of Sen. Dale Volker, R-Depew, Erie County, against Democrat Kathy Konst in a district that runs across western New York into Livingston and Ontario counties. Volker has a 50 percent to 39 percent lead, though Konst has gained six percentage points since the last Siena poll – making it the closest of the four races polled by Siena today.

In a critical Long Island race, Democratic Sen. Craig Johnson has a 50 percent to 35 percent lead over Republican Plandome Manor Mayor Barbara Donno. A poll last month showed Johnson, who won the seat in a special election in 2007 after then-Republican Sen. Michael Balboni joined the then-Spitzer administration, with a 49 percent to 25 percent lead.

The polls were conducted in each Senate district from Oct. 27-29 to about 400 registered voters. Each poll had a margin of error of about 4.8 percent.