At a news conference, Barber charged that an ID requirement amounts to a poll tax as it would force people to pay to get a license in order to vote - which is a constitutional right.
"It's a poll tax bill disguised as voter ID, that can effectively disenfranchise 600,000 North Carolinians," said Barber.
Supporters of a voter ID law say it's needed to stop voter fraud.
"We cannot fall for this kind of rhetoric. We need ID for prescription drugs, to use a credit card, to fly on planes, so why not to vote? Because voting is the constitutional right, those things are privileges," Barber explained.
While many mainstream Republicans - including Governor Pat McCrory - have said they support a voter ID law, Barber charged the proposal is the work of far-right Republicans and Tea Party activists who want to restrict early voting, same-day registration, and Sunday voting. He claimed Thursday it's intended to weed out minorities, the elderly, and women.
"It's about the Constitution. The law says no federal state or local government can in any way impede people from registering to vote," offered Barber.
But Republicans insist the measure is a must to protect the integrity of the election system.
Susan Myrick, an election policy analyst with Civitas, says they've done extensive research on the subject, looking at how it's worked in other states.
"Especially in Georgia and Indiana in their implementation of their voter ID bills they haven't seen to come to pass all of the frightening things that opponents of voter ID have said would come," Myrick said.
Myrick also says this is not a right-wing movement to keep certain demographics from voting for the left, as the NAACP is claiming.
"Absolutely not. You can look at Civitas polls or look at Elon or national polls and see the overwhelming majority of the people think it's only common sense to show an ID to vote," she said.
But Barber says such polling is misleading, because most people don't realize that in North Carolina lying to vote is a felony punishable by up to five years in prison, which he says already serves as a deterrent to voter fraud.
And, he maintains the law is unnecessary in the first place, since there's been no evidence of this type of voter fraud in the past.
Civitas counters that there's little proof fraud hasn't occurred because it's hard to track.
Opposition to voter ID may be largely symbolic. Democratic groups have acknowledged they don't have the votes in the General Assembly to stop it.