Hawaii island Democratic Party groups have sued the state Reapportionment Commission, arguing that the inclusion of nonpermanent residents favors Oahu and denies the shifting of a state Senate seat to their island.

Stanley Roehrig, a Hilo attorney and former state representative, filed the lawsuit Monday electronically on behalf of Sen. Malama Solomon and members of the Hawaii County Committee of the state Democratic Party.

The lawsuit challenges the new political boundary maps drawn to reflect changes in the state’s population over the past decade. It asks that the current plan for apportioning the state’s 25 Senate seats be declared invalid and that a new plan be drafted.

"The final Senate plan is based on the Reapportionment Commission’s use of the wrong population base and, as a consequence, improperly apportions the seats of the state Senate," denying Hawaii County a fourth Senate seat, the lawsuit states.

Reapportionment Commission Chairwoman Victoria Marks has said she expected a legal challenge and asked commission staff to prepare alternate maps to give the court alternatives if it determined that new maps were needed. The other alternative would be to appoint a special master to draw new maps.

Marks said the commission did the best it could with the information it had.

At issue is the definition of "permanent resident." The state Constitution says reapportionment and redistricting should be based on the number of total "permanent" residents, but it does not define permanent.

Commissioners voted 8-1 in June to include so-called "nonresident" military members and their dependents — people who live in Hawaii but claim official residency elsewhere — along with nonresident students and incarcerated felons in the total state population, based largely on the inability to locate those residents and determine their residency status.

Officials said changes in privacy laws made it impossible to extract all of the nonresidents — about 80,000 people — from the population using the same methods as in previous years.

The commission eventually was able to obtain more data to determine the location and residency status on about 16,000 of them. Commissioners voted 5-3 last month to exclude those 16,000 residents, but their extraction does not change the population base enough to shift a Senate seat.

The lawsuit names Gov. Neil Abercrombie, the state Office of Elections, Chief Election Officer Scott Nago and members of the Reapportionment Commission as defendants.

Hawaii island groups were backed by an opinion from the state attorney general’s office that stated if the nonresidents were included, the decision likely would be overturned by the state Supreme Court.

"This petition involves the fundamental question of whether or not the 2011 Hawaii Reapportionment Commission can willfully ignore the Hawaii state Constitution," the lawsuit states.

The Reapportionment Commission is scheduled to meet Thursday to decide on a plan to stagger the 25 Senate seats by having 12 of them come up for re-election again in 2014.