A group of Prince George’s County residents who allege that the County Council secretly approved zoning legislation without a public hearing two years ago is engaged in a legal battle to overturn the measure.

The residents say the council approved it without giving the public ample opportunity to state any objections. The bill, known as Subregion 5 Master Plan, included numerous sectional map amendments and would allow more development in some rural parts of the county, dramatically altering the area’s landscape.

“It’s not that we’re against development,” said Mary Forsht-Tucker, a board member of the Indian Head Highway Area Action Council, a civic group in the Fort Washington area. “We want input.”

But David Billings, a spokesman for Circuit Court Clerk Marilynn M. Bland, the former council member who represented the area and pushed through the amendments, said the process was open and residents were given proper notice.

“We had quite a few hearings,” said Billings, who worked as Bland’s chief of staff while she served on the council. “We pushed it back so that all those who wanted to testify could testify.”

The residents mounted their campaign two years ago. They sent 387 postcards and letters to council members. They rallied at the County Administration Building. And last week they argued against the process during a court hearing.

“This was the only way to let them know and let the new [council members] know that you are going to be held accountable,” said Patricia O’Neal, a plaintiff in the lawsuit and president of the Windbrook Area Citizens Association in Clinton. “Even if we lose this case, it’s our way of saying, ‘Okay, we’re watching you.’ ”

Susan Gray, an attorney representing the residents, said the council added “a slew of amendments after the public hearing. . . . The approved plan has no resemblance to what was shown to the public.” The residents argue that the public received no notice about the amendments. Gray said state law requires a public hearing on amendments added to comprehensive plans.

Karen Campbell, a spokeswoman for the council, said the council does not comment on pending litigation.

Many of the residents said their main issue was the council’s decision to fold in the rezoning of Hyde Field airport into the master plan amendments. The mixed-use development calls for replacing the Clinton airport with 2,100 housing units and about 300,000 square feet of retail space.

Several residents said the process went against good government and transparency.

“The council does not like to operate in the sunshine and it never has,” said William Cavitt, vice president of the Indian Head Highway council.

Cavitt said his group has pushed for years for greater transparency and citizen participation. Among other things, it has asked for live streaming of council and planning board sessions. The two bodies began showing their sessions on the Internet this year. But committee hearings, where much of the debate takes place on bills, are not online.

Council member Mel Franklin (D-Upper Marlboro), who was not on the council at the time, said he could not comment specifically on the lawsuit. He said, however, that he supports increased public input.

“Clearly, going forward, we have to make sure there is public engagement,” said Franklin, who, as a resident, protested with O’Neal and Forsht-Tucker outside the County Administration Building in September 2009, the day the controversial vote was taken.

“We have to go above and beyond, particularly with master plans, because they affect people’s lives for a long, long time,” he said.

The lawsuit is the second legal challenge against the vote.

The Accokeek, Mattawoman, Piscataway Creeks Communities Council filed a petition two years ago, arguing that the council violated a Maryland public ethics law when it approved the measure. The group said the council, which sits as the District Council when it hears zoning issues, did not file affidavits regarding campaign contributions made by property owners who might benefit from zoning changes. The case is pending before Prince George’s Circuit Court Judge Leo Green Jr.

“I’m hopeful that the new members’ approach will be different,” Forsht-Tucker said, “that things will not be done in backrooms.”

Subregion 5 covers 75 miles in the southwestern region of the county, running through Clinton, Accokeek, Piscataway, Tibbett and Brandywine. It is bounded by Andrews Air Force Base to the north and Charles County to the south.