HARRISBURG— Dozens of Pennsylvanians testified Friday before a special panel in charge of redrawing the state’s legislative boundaries, but only after Occupy Harrisburg activists staged a surprise protest that delayed the start of the hearing.

Just as the session before the Legislative Reapportionment Commission was scheduled to begin, about two dozen protesters interrupted with a fast-paced call-and-response chant that drowned out the chairman’s attempts to restore order.

The Republican-crafted redistricting plan would move one Senate seat from southwestern Pennsylvania to Monroe County in the Pocono Mountains. In the House, it would add districts in Lehigh, Berks, Chester and York counties while eliminating seats in Allegheny, Philadelphia and Erie counties.

The purpose of redistricting is to equalize the population in the 203 House districts and 50 Senate districts to conform to the 2010 census and balance representation in the Legislature.

Barry Kauffman, the state director of Common Cause, and Lora Lavin of the Pennsylvania League of Women Voters, urged the commission to hold more public hearings on its plan and to post all alternative redistricting plans and maps on the commission’s website.

“While the commission has had nearly eight months to work on the data to define district boundaries, citizens have had just under three weeks to evaluate and comment” on the preliminary plan, Kauffman said.

Most of the testimony focused on specific areas where the changes have stirred opposition.

One was GOP Sen. Jeffrey Piccola’s district, which would assume a C-shape that passes through five counties and excludes Harrisburg — the fiscally troubled state capital facing a state takeover authorized by a new law that Piccola helped write. Piccola said last week he does not plan to seek re-election in 2012.

If approved, the new district “would become the new poster child for partisan gerrymandering,” Lavin said.

Patty Kim, the Harrisburg City Council vice president and a Democratic candidate for the state House, said the district was clearly engineered to ensure Piccola’s re-election.

Local officials protested the proposed relocation of Democratic Sen. James Brewster’s district from Allegheny and Westmoreland counties in southwestern Pennsylvania to Monroe and Northampton counties in the northeast.

The commission adopted the GOP proposal as its preliminary plan by a 3-2 vote on Oct. 31, beginning a 30-day public comment period, and the panel will have up to another month to approve a final plan.

A second hearing is set for Wednesday.