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.

Patrick said the 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 up front for the licenses, nor how long the licenses would last.

The governor said developing casino gambling in the state was part of his overall plan to advance initiatives that provide long-term 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," the governor 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.

He also said trust funds would be created to deal with public health issues linked to gambling and "community mitigation" -- to help towns offset the costs of hosting a casino.

DiMasi has opposed an expansion of gambling in the past. But in the weeks leading up to Patrick's announcement, the Boston Democrat said he would keep an open mind.

Massachusetts Senate President Therese Murray has said she supported expanded gambling.

Patrick's plan follows a proposal by the Mashpee Wampanoag tribe to build a $1 billion casino on land it owns in Middleborough. 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 in the state.

The governor said at least one of the licenses would have "a Native American component."

"I fully expect that we will give special weight to the tribe. I think they have a special role and interest," he said of the Mashpee Wampanoags.

"I just can't tell you whether that means reserving one of the licenses, or giving special weight to one or more of the licenses with the tribe as a partner," he said.

The Aquinnah Wampanoag Indians have declared that they would also open a casino if their Mashpee counterparts do the same.

Consumers spent $32 billion in commercial casinos in 11 states last year - more than consumer spending on specialty coffee and books combined, according to the American Gaming Association.