Legislation that was hurriedly revised by Republicans in the North Carolina legislature would make extensive changes to the state’s voting laws that could marginalize certain groups, voting advocates say.

House Bill 589, which initially would have required voters to present photo identification before casting a ballot, sat stagnant for three months after the House approved it. Then, in a sudden flurry of activity over the last few days, Senate Republicans piled on several substantive alterations to voter registration, early voting and campaign financing among other modifications, before the Senate Rules Committee passed the bill on a hasty voice vote July 23, according to the Associated Press.

Activists say the contents of the legislation and the fact that Republicans introduced and pushed the changes through in the last week of the session raises troubling questions.

“We are deeply troubled that the Senate would introduce such sweeping changes to our state’s election laws in the final hours of this year’s legislative session with limited public input and without thorough examination,” said Brent Laurenz, executive director of the nonpartisan N.C. Center for Voter Education, in a statement. “Rushing this serious legislation is unworthy of the legislature’s solemn duty to serve the people of North Carolina.”

The new omnibus bill adds a slew of additional provisions. It shortens early voting by a week, eliminates same-day registration, increases restrictions on provisional voting, ends pre-registration for high school students before their 18th birthday and prohibits counties from extending early voting hours on the Saturday before Election Day to accommodate emergencies, such as long lines.

The measure also increases maximum individual campaign contributions from $4,000 to $5,000, it repeals publicly funded elections for judicial races, and weakens disclosure requirements showing who pays for political ads.

As per the bill’s original intent, voters would have to present a government-issued photo ID at the polls and student IDs issued by the state’s public universities and community colleges would not be accepted. It also would allow any registered voter of a county to challenge the eligibility of another voter, it eliminates straight-ticket voting and outlaws paid voter registration drives.

Supporters of the legislation say it is necessary to combat voter fraud, which they say is widespread and usually undetected.

“People need to have confidence in the fact that everyone only votes once, and that their vote matters, and establish integrity in the electoral process,” state Sen. Bob Rucho (R-Mecklenburg), who guided the bill through committee, told the AP. “I would hope we can pass this bill and re-establish a level of integrity and confidence in the electoral system.”

But Democrats and nonpartisan voting activists say GOP claims of voter fraud are often exaggerated and have little basis in fact. Instead, they claim, the measures are often aimed at suppressing the votes of African Americans, Hispanics, the young, the elderly and the disabled.

“You’re going to have a situation with this bill where you’ve got people who voted all their lives that are going to show up at the polling place and not going to have what they need to vote,” said state Sen. Martin Nesbitt (D-Buncombe), the Senate minority leader, as quoted by the AP. “That is outrageous.”

North Carolina’s House Bill 589, which is expected to be passed by the majority-Republican Senate, is the latest in a series of Republican-led efforts to suppress voter turnout, activists say. And such efforts are likely to balloon in number in the wake of the Supreme Court’s decision last month that stymies enforcement provisions of the Voting Rights Act that were meant to protect against racial discrimination in the election process.

“This is the single worst bill we have seen introduced since voter suppression bills began sweeping the country two years ago,” said Barbara Arnwine, executive director of the Lawyers’ Committee for Civil Rights Under Law, in a statement. The measure “would make a mockery out of the democratic process in the state if enacted into law.”