CHICAGO (Reuters) - A vote on an Ohio bill that would end collective bargaining rights for public employees could come as early as Wednesday, a state senator said on Sunday.

Meanwhile, in Indiana, Democratic state representatives could stay in Illinois all week to avoid votes on bills they say would harm workers' rights, officials said.

While the massive protests in Wisconsin over proposed collective bargaining limits have been in the national spotlight, debates over curbs on unions also have roiled other Midwestern states.

In Ohio, a senate bill likely will be softened by amendments before it comes to a committee hearing on Tuesday because the Republican-backed bill currently does not have enough Republican votes, despite a 23-10 majority, an Ohio Senate Democrat said on Sunday.

"If they had the votes before, we'd be already done," said State Sen. Joe Schiavoni, who does not support the bill.

Schiavoni said Senate Republicans are working on a substitute bill affecting collective bargaining which could be voted on by the full senate on Wednesday.

Indiana house Democratic spokesman John Schorg said he was aware of no progress in negotiations between Republicans and Democrats on Sunday.

The actions by Indiana legislators mimic what has happened in Wisconsin, where all 14 senate Democrats have left the state to avoid voting on a proposed collective bargaining bill.

The Wisconsin senators had no plans to return on Sunday, a spokesman told Reuters.

The Indiana Democrats say state house Republicans have offered multiple bills which contain provisions that restrict employee rights. Democrats say there has to be an agreement to take those bills off the table before they will discuss other legislation.

Indiana Gov. Mitch Daniels, a Republican, have said the Democrats were showing "complete contempt" for the democratic process.

A crowd estimated at more than 70,000 people on Saturday in Madison, Wisconsin, waved American flags, sang the national anthem and called for defeat of Republican governor Scott Walker's proposal to curb public union collective bargaining.

(Writing by Mary Wisniewski, Editing by Peter Bohan)

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