Republicans in Wisconsin's state senate have pushed through the most severe assault on trade union rights for a generation, taking opponents by surprise and passing a measure in barely 30 minutes that sharply curtails collective bargaining for public sector workers.

The procedural ruse by the Republicans hands victory to the new rightwing governor of Wisconsin, Scott Walker, in his three-week standoff with the state's Democratic senators. All 14 Democratic members of the chamber had fled to Illinois where they have been in virtual hiding in order to frustrate the governor's plans by preventing a vote on the proposed measure.

Under the state senate's rules, any bill that was budgetary in nature has to have a quorum of at least 20 senators. That meant the 19 Republican senators needed at least one Democrat present to move to a vote.

But in a shock move, the Republicans unhooked the overtly financial clauses from the bill, and pushed the rest through in record time, arguing that because it was no longer related to the budget it required no quorum.

The new bill that cleared the senate provides for a drastic reduction of collective bargaining rights for public sector workers, excluding police and fire officers who are exempt. Unions can no longer negotiate over pay rises above the rate of inflation, and they have been forced to accept increased payments to their pension and health schemes equivalent to an 8% pay cut.

The bill went through on an 18-1 vote of only Republican senators amid dramatic scenes in the state capitol. Up to 2,000 protesters who had amassed in the building since the confrontation began three weeks ago chanted: "You are cowards!" and "The whole world is watching!"

Walker celebrated the rupture of the stalemate saying "the action today will help ensure Wisconsin has a business climate that allows the private sector to create 250,000 new jobs".

But Democrats cried foul, saying that by springing the vote on the senate the Republicans had violated their rights.

The leader of the senate Democrats, Mark Miller, released a statement from exile in Illinois saying: "Their disrespect for the people of Wisconsin and their rights is an outrage that will never be forgotten. Tonight, 18 senate Republicans conspired to take government away from the people. We will join the people of Wisconsin in taking back their government."

Wisconsin has become a litmus test of the new more aggressive style of Republican politics that were emboldened by the Tea Party-fuelled victories in the mid-term elections last November. Walker took up his post in January and quickly became the most extreme of a new class of Republican governor that has targeted the public sector unions.

Similar battles are sweeping through the US, from Indiana, where senate Democrats are also holed out in Illinois to avoid a quorum, to Idaho, Ohio, Michigan and Tennessee.

The Wisconsin bill has to pass through the state's second chamber, the assembly, but that is considered a foregone conclusion.