Boston – Gov. Deval Patrick is preparing to unveil a proposal as early as Monday to bring three full-scale casinos to Massachusetts, a plan he hopes will generate hundreds of millions in revenues and thousands of jobs.

Gambling opponents are already mobilizing against the plan, which they say won’t be the cash cow Patrick hopes and will end up costing the state money while destroying its character.

Under Patrick’s plan, the three casinos would be distributed in the western, southeastern and greater metropolitan Boston regions of the state, a source familiar with the plan told The Associate Press on condition of anonymity because the plan had not been released yet.

The three license would be put up for bid. The competitive process could generate hundreds of millions in direct revenues for the state.

The plan comes on the heels of a proposal by the Mashpee Wampanoag tribe to build a USD 1 billion casino on land it owns in Middleborough. The plan needs legislative support, and gubernatorial backing is vital.

The tribe could either try to outbid others for one of the licenses proposed by Patrick, or continue along a more lengthy track to win federal approval. That could result in a fourth casino.

A spokeswoman for the tribe hailed the announcement, saying Patrick’s plan would clear away an obstacle to the construction of a casino — something the tribe claims as a sovereign right.

„The tribe has been clear it wants to build a casino and this opens the door to that,“ said spokeswoman Amy Lambiaso.

She also raised the possibility of the tribe bidding on all three licenses.

„Absolutely everything is on the table,“ she said.

Patrick’s plan, first reported in the Boston Sunday Globe, would not allow slot machines at the state’s existing dog and horse tracks — something the tracks have been seeking for year. The tracks could still try to outbid others for one of the licenses.

Gambling opponents were quick to attack Patrick’s plan as shortsighted.

Some of the stiffest opposition comes from the Massachusetts House, where representatives have regularly shot down expanded gambling proposals — most recently last year when the House killed a measure to install slot machines at racetracks by a 100-55 vote.

„I am profoundly disappointed in this governor,“ said state Rep. Daniel Bosley, D-North Adams. „There really isn’t new revenue here. It just gives him cover to spend more money.“

Bosley said much of the anticipated casino revenue is revenue the state would have made from other sources. Much of the rest of the revenue would be eaten up by the social costs of gambling, from increased crime to gambling addiction, he said.

Relying on gambling would also undercut other efforts to build up the state’s economic base, Bosley said.

„Casinos suck the oxygen out of the air for other businesses,“ he said. „That’s going to be his legacy. That’s what he’s going to be know as — the governor who brought in casinos.“

A spokesman for House Speaker Salvatore DiMasi, D-Boston, said DiMasi is waiting to take a look at what Patrick proposes.

Patrick is under pressure to find new revenues. He has proposed big ticket items from a USD 1 billion, 10-year life science project, including the world’s largest stem cell bank, to a USD 1.4 billion commuter rail line from Boston to Fall River and New Bedford.

The state is also looking for extra money to close an estimated USD 15 to USD 19 billion gap in transportation spending over the next 20 years.

Patrick’s plan has its supporters in the Legislature, including Senate Ways and Means Chairman Steven Panagiotakos, D-Lowell.

Panagiotakos said three casinos makes sense, especially one in the greater Boston area to capture those who might head north if New Hampshire opens a casino near the border.

„It’s absolutely essential,“ he said. „Even if we had one in Southeastern Massachusetts and Western Massachusetts, we would still be losing our greatest population center to New Hampshire.“

He also predicted support for Patrick’s plan in the Senate, which has backed other expanded gambling proposals.

Casino gambling, a perennially divisive issue on Beacon Hill, gained momentum after the Mashpee Wampanoags, who shared the first Thanksgiving with the Pilgrims in 1621, won federal recognition in February from the U.S. Department of Interior’s Bureau of Indian Affairs — after 32 years of legal tug-of-war.

Gambling supporters were also buoyed by the election of Patrick, who signaled a willingness to examine the issue. His predecessor, Mitt Romney, had vowed to veto bills to expand gambling.

Treasurer Timothy Cahill has said the state should try to beat the tribe to the punch by building one or more resort casinos.

Most legal experts agree that legislative approval is required for a tribe to open a full-scale casino.

What’s available right now to a federally recognized tribe is a so-called „level 2“ gaming facility, with machines similar to slot machines. If the state changed the law to allow „level 3“ gambling, the tribe would be able to build a casino with slot machines and games such as poker, blackjack and roulette.

The state’s only other federally recognized tribe, the Aquinnah Wampanoag Indians, have declared that they’ll seek to open a casino if the Mashpee Wampanoags reach a deal with Massachusetts.

Foxwoods Resort Casino and the Mohegan Sun casino — the two Indian-run casinos in southeastern Connecticut — pump more than USD 400 million into the state’s general fund each year, as a result of compacts with the state.