"Rally for New Hampshire" is scheduled for noon at the State House Plaza.
Wednesday's vote on House Bill 2 came a day earlier than expected, catching state workers and other advocacy groups off guard.
"Speaker (William) O'Brien purposely moved up votes on the budget, and the union-busting amendment in particular, because he was afraid to face the wrath of thousands of New Hampshire voters who will be on the State House steps ... in vast disapproval of the extreme agenda of the House leadership," said Diana Lacey, president of the State Employees Association.
NH Cares, a statewide network of health and human service providers, trumpeted the rally on its website: "Let's make our voices heard. We care! We count! We matter!"
Anticipating a large crowd, the group provided advice on parking, planning and themes for protesters to stick to if they wanted to make signs or posters.
"People above Politics," "NH Can Do Better," and "Lean, Not Mean" are offered as themes for the rally.
Some organizers say they expect up to 5,000 people to attend.
"Anytime people's human rights are being taken away, people tend to stand up and say no," Bill McQuillen, Portsmouth firefighter, told CNN affiliate WMUR.
Passage of the bill would limit the ability of labor unions representing state workers to collectively bargain on issues like wages, hours, working conditions and benefits.
While the vote has roiled state workers from teachers to firefighters, House Republicans who back the bill say they have their supporters too.
"If you look at my emails, I've got 8-to-1 ... in support of what we're doing here to protect the taxpayers," said Rep. Al Baldasaro from Londonderry, according to WMUR.
Similar efforts by legislatures to change collective bargaining laws in Wisconsin and Ohio have ignited passionate responses. The states' governor and Republican lawmakers have said the changes were needed as they grapple to limit spending.
Demonstrators occupied the Wisconsin capitol building for weeks before the legislature passed a law that curbs the collective bargaining rights of most state employees. A Wisconsin judge has put the law on hold.
On Wednesday, the Ohio state legislature passed its own legislation that would limit collective bargaining rights by barring Ohio's public employees from striking. The bill is now bound for Ohio Gov. John Kasich's desk to be signed into law, possibly this week.
Kasich has argued that Ohio Senate Bill 5 is crucial to closing an $8 billion budget shortfall and bringing public-sector benefits in line with those in the private sector.
CNN U.S., Thurs Mar 31 2011
Byline: Ed Payne