State officials vigorously defended a new 3,000-person Statehouse capacity limit on Tuesday, saying it was driven by public safety concerns and not by political motives as labor unions and other opponents maintain.

The capacity limit and other tighter security policies are expected to see their first test Wednesday, with perhaps hundreds of labor union members arriving on the opening day of this year's legislative session to protest a push by majority Republicans to approve a right-to-work proposal.

The leader of the state agency that oversees the Statehouse and its grounds said that agency, the state fire marshal's office and state police decided to review the capacity question on their own after similar protests during last year's legislative session drew large, boisterous crowds.

Department of Administration Commissioner Robert Wynkoop said Republican Gov. Mitch Daniels' office wasn't told about the decision until Thursday, a day before the new policy was announced.

Wynkoop and other officials said they expected the capacity limit would rarely be reached but that it wasn't possible to keep an exact count and that there would be constant reviews of the policy.

"We are not keeping people out," Wynkoop said. "That is the furthest thing from what we're trying to do here."

The new limits will cap the number of Statehouse visitors at about 1,300 because it takes into account 1,700 people who work there or who have access passes, including about 250 lobbyists, he said.

The Indiana AFL-CIO intends to monitor whether any people aren't able to enter the Statehouse on Wednesday and is considering possible legal action to fight the limits, union spokesman Jeff Harris said.

"Citizens won't be allowed in, but lobbyists will," he said. "That's despicable."

The new policy raises questions about whether members of the public might not be able to attend committee hearings or seek to speak with their legislators in person unless they have made previous arrangements.

It is unclear how often the new limits might lead to shut offs of public access. State police Capt. David Bursten said the most visitors the Statehouse had in one day during the last legislation session was about 1,500, which would exceed the new cap by a couple hundred people.

The new security policies also prohibit visitors from bringing in cans or glass bottles, noisemakers and signs larger than 2 feet by 2 feet. Officials have also newly designated a Statehouse elevator for use only by legislators and staff members and plan greater restrictions on people gathering outside the House and Senate chambers.

State Fire Marshal James Greeson said the capacity limit is based on how quickly the building could be evacuated. He said his staff calculated that with the four exits on the main floor of the 1880s Statehouse, up to 3,200 people could get out within about five minutes.

The governor's spokeswoman said the security plan was completely developed by the safety officials.

"He trusts the agencies will do the right thing," spokeswoman Jane Jankowski said.