PORTLAND (AP) – Proponents are weighing a referendum campaign to promote a plan to let home sellers bypass real estate agents and place their properties online in a statewide multiple listing service.

If adopted, the proposed service could compete with a database owned by the Maine Association of Realtors and enable homeowners and developers to list homes for a monthly fee and make the information available to anyone with a computer. A real estate agent selling a home could be required to list the property with the new service if a homeowner requested that placement.

Two former Republican lawmakers – Stavros Mendros of Lewiston and Adam Mack of Standish – said they are preparing a petition drive this fall to collect the 51,519 signatures needed to place the idea before Maine voters in November 2007. Details are still being developed.

“The goal is to help the little guy save money and make the marketplace more efficient,” Mack, who develops apartment projects, told the Portland Press Herald. He said brokers “control a monopoly.”

Linda Gifford, the legal counsel for the Maine Association of Realtors, said realtors already face competition from newspapers, online listings and other real estate agents.

“The system we have is working just fine,” Gifford said.

A database operated by and accessible to real estate agents, Multiple Listing Service, compiles thousands of property listings into a single source.

Supporters of an open multiple listing service say they need to make the listing legally binding so real estate agents would have to include their properties on the Web site if requested by clients.

A catalyst for the Maine petition drive is San Francisco lawyer Dave Barry, who submitted a report last year to the Federal Trade Commission accusing the industry of anticompetitive practices.

Barry, who tried to get a similar ballot initiative before voters in California but said running the campaign in such a large state was too expensive, contacted Mendros, who agreed to work on the measure.