BOSTON – Gov. Deval Patrick on Monday proposed licensing three resort casinos in Massachusetts in a move he said would generate $400 million to $450 million in annual tax revenue that would be spent on transportation upgrades and property tax relief.

Under the plan, the “tasteful and appropriate” casinos would be distributed one each in the western, southeastern and metropolitan Boston regions of the state, Patrick said.

The licenses would be put up for bid in a competitive process open to Indian tribes and casino companies.

Patrick’s plan would not allow slot machines at the state’s existing dog and horse tracks – something the tracks have been seeking for years. The tracks still could try to outbid others for one of the licenses.

The issue is of more than passing interest to Maine.

The only slot gambling in the state is at Hollywood Slots of Bangor, which reported gross revenues of $564 million and net revenues of more than $37 million from its temporary home on Main Street. Its owner, Penn National Gaming Inc., is building a $131 million racing casino on Main Street in Bangor, scheduled to open next year.

In addition, lottery gambling contributed $51 million to Maine’s General Fund last year on sales of $226 million.

And a statewide referendum is scheduled this November on the Passamaquoddy Tribe’s proposal to run a harness racing track with up to 1,500 slot machines in Washington County.

In Rhode Island, Gov. Don Carcieri said Monday he opposes bringing full-fledged casinos to Rhode Island. But his administration wants to expand the games allowed at two state-approved slots parlors in Lincoln and Newport.

Since Connecticut already has casinos and Massachusetts may follow, Carcieri said, he thinks it’s unlikely a Rhode Island casino would bring in out-of-state dollars.

In Massachusetts, lawmakers must approve expanding legalized gambling beyond the state lottery and four racetracks. State House Speaker Salvatore DiMasi said Monday he was not persuaded by Gov. Patrick’s plan.

“I will obviously be discussing this with members of the House, some of whom have serious and justified concerns about creating a casino culture here in the commonwealth,” DiMasi said. Senate President Therese Murray has said she supports expanded gambling.

Patrick said the Massachusetts casinos would generate more than $2 billion annually in economic activity and create “good jobs at good wages.” He said “tens of thousands” of construction jobs would be created to build the facilities.

“With that kind of economic benefit, we cannot reject the gaming industry out of hand,” he said.

Patrick did not address how much money could be raised upfront for the licenses, or how long the licenses would last.

“Casino gambling is neither a cure-all nor the end of civilization,” Patrick said. “On balance, however, and under certain conditions, I believe resort casinos can work well in, and for, the commonwealth.”

Gambling opponents already are mobilizing against the plan, arguing the casinos won’t be the cash cow Patrick hopes and will end up costing the state money – primarily lottery revenues – while destroying its character.

“I didn’t make this proposal without understanding that it’s going to take some work to get it passed,” Patrick said.

The governor said developing casino gambling in the state was part of his overall plan to advance initiatives that provide sustainable growth for Massachusetts.

“Destination resort casinos can serve a useful role in our overall economic plan,” he said.

Patrick is under pressure to find new revenues as the state looks for extra money to close an estimated $15 billion to $19 billion gap in transportation spending over the next 20 years.

“Our roads, rails, buses and bridges are showing the effect of over 16 years of neglect,” he said.

Patrick also wants to spend the revenue to fulfill one of his campaign pledges to reduce property taxes, which he said he would do through tax credits.

The governor also has proposed big-ticket items including a $1 billion 10-year life science project that would include the world’s largest stem cell bank and a $1.4 billion commuter rail line from Boston to Fall River and New Bedford.