The region's two largest coalitions for the homeless are merging into a single organization that will expand Quincy's nationally recognized housing initiative to communities as far away as Middleborough and Plymouth.

Father Bill's Place in Quincy and MainSpring Coalition for the Homeless in Brockton, both founded two decades ago, made their announcement today, effective immediately. They say the combined resources of the new organization - called Father Bills & MainSpring - will better advocate for state and federal funding.

The guiding philosophy will be to shift from emergency shelter to permanent housing, with the eventual goal of eliminating homelessness altogether.

The merger comes as Quincy officials announced this week that a shelter opened by Father Bill's Place will permanently close due to a 20 percent drop in chronic homelessness over the past three years. They credit the drop to the transitional and supportive housing program.

The new organization will serve more than 100 families a day and a few thousand people per year, according to the coalition's president and chief executive officer, John Yazwinski. Shelters and housing are in Quincy, Brockton, Weymouth, Plymouth, Stoughton, Middleborough, and Hull.

"These groups both started out as small, short-term solution and response, but have grown to become voices for change," said Yazwinski, who joined Father Bill's Place in 1996. "We realized that we were competing for resources, and wanted to combine our strengths to push for better funding and policy changes."

The "housing first" initiative of Father Bill's Place has offered subsidized housing to the working poor, Yazwinski said, and has been duplicated by other cities and or ganizations since its inception in 2005.

In Quincy, statistics have shown that the program has had an 86 percent success rate in keeping people out of shelters and off the street, he said. The city is on a plan to eliminate homelessness by 2015.