The anti-tax Tea Party is gaining traction as 41 percent of likely voters support the movement publicly, up from 34 percent in August. 

The uptick comes as lawmakers prepare to debate the fate of Bush-era tax cuts. 

Friday's poll results could potentially make it more difficult for Republicans to support President Obama's plan to continue the tax breaks benefiting the middle-class while allowing the ones for the wealthy to expire on schedule at the end of the year. 

Sources said there is growing concern among Republicans that supporting any tax increase might provoke opposition from the Tea Party and hurt their reelection bids.   

The Tea Party has supported upstarts that have already unseated Sens. Lisa Murkowski (R-Alaska) and Bob Bennett (R-Utah). And some Republican senators that aren't even up for reelection this year are tacking further to the right in their positions to keep the Tea Party from supporting a candidate in their home state.

"We are staring to see an interesting trend emerging from the [poll]," said Vik Rubenfeld, who oversaw the survey. "The number of Tea Party supporters who are willing to endorse the movement publicly has jumped seven points in one month, steadily rising from 34 to 41 percent. Meanwhile, overall support for the Tea Party remains stable among likely voters."