COLUMBUS, Ohio (Reuters) - Ohio's state capital is expected to be the site of massive union protests on Tuesday as legislators consider a bill to curtail collective bargaining rights for public workers and eliminate their right to strike.

Republican supporters of Senate Bill 5 say the limits to public workers' ability to bargain are necessary to give local governments flexibility and help reduce the state's two-year budget deficit of about $8 billion.

"Over time, these contracts have often incorporated demands that frankly belong to public employers rather than employees -- things like specifying the number of workers that should be assigned to a specific job," said Jason Mauk, a spokesman for Ohio State Senate Republicans.

He said the bill provides "some balance to the process."

But labor unions and Democrats have protested that the bill goes too far in sacrificing public workers' rights.

Senate Bill 5 is expected to come before a Senate committee Tuesday, and may be voted on by the full Senate this week. Workers plan protest rallies Tuesday and Wednesday.

The bill is being modified from its original form, in which it would prohibit collective bargaining for 42,000 state workers in addition to 19,500 workers in the state's university and college system. This would end a right established in 1983 for Ohio's public-sector workers.

For local governments that bargain with unions representing some 300,000 workers including police, firefighters, and public school teachers, the bill removes health care and some other benefits from the negotiating process.

Proposed changes to the bills, which Mauk said will be incorporated into its language when the bill is reviewed in committee, restore collective bargaining power for public employees on wages, but also prohibit striking for any public employee on the state and local level, said Mauk.

He said the changes bring the bill more in line with the views of Gov. John Kasich, who wanted to preserve some collective bargaining but didn't want strikes.

More Republican amendments will become public at the committee hearing, Mauk said.

Democratic State Senator Joe Schiavoni predicted the amendments would likely soften the bill, because Republicans, though a majority of 23-10 in the senate, did not have enough Republican votes to pass it in its current form. He thinks the state should sit down with unions and solve "inefficiencies" in collective bargaining, but does not support the bill.

Like Wisconsin, Ohio has a new Republican governor and Republican majorities in both legislative houses.

Madison, Wisconsin is in its third week of protests over a bill that would limit collective bargaining for public workers. Republicans there have offered no compromises on the bill.

(Editing by Jerry Norton)