Casino competition is heating up in the last Massachusetts region awaiting a gambling development.

Marina Bay and Granite Links Golf Club developer Thomas O’Connell is leading a development partnership, Notos Group LLC, for Wareham Park. The more than $300M gambling proposal includes a horse track, restaurants, a slots parlor, a hotel, a ballpark for the Cape Cod Baseball League’s Wareham Gatemen and other entertainment venues.

“The Notos Group will ask the Legislature to give the Massachusetts Gaming Commission the discretion to approve a gaming facility that reflects current market realities,” the development team stated in press materials released Tuesday.

The project needs to obtain the state’s remaining available casino license, slated for Southeastern Massachusetts (referred to as Region C by the Massachusetts Gaming Commission).

Massachusetts already has two full-scale casino resorts (those with table games and slots) at the MGM Springfield and Encore Boston Harbor. The state’s only slots parlor is Plainridge Park Casino in Plainridge.

It would also require the MGC to rework the licensing structure for the southeast region of the state. Part of the 2011 law that cleared the way for legalized casinos in Massachusetts requires developers spend at least $500M on a casino resort.

The state required its only slots parlor to have at least a $125M investment. Wareham Park would need the state to allow a slots parlor license for Region C instead of a full casino resort.

The proposal comes just as horse racing winds down at Suffolk Downs in East Boston and as competition heats up for casinos in southeastern Massachusetts.

Chicago-based developer Neil Bluhm has proposed a $700M casino resort in Brockton, the Mashpee Wampanoag tribe wants to build a $1B casino in Taunton and the Aquinnah Wampanoag tribe’s plan for a Martha’s Vineyard casino continues to be held up in a court battle.