New Mexico state lawmakers will debate a proposed agreement between the state and the Navajo Nation later this year that could allow the tribe to operate as many as five casinos around the state for the next two decades.

The deal, struck between tribal leaders and Gov. Susana Martinez (R), would allow Navajo officials to build two new casinos. At the moment, the tribe operates two casinos regulated by the state, and one that has stakes low enough to avoid state regulation.

Martinez and tribal leaders reached the deal last year, but state lawmakers balked at approving it after complaining they didn’t have sufficient time to comb through the details. Several other New Mexico tribes worry that the added competition will cut into their business, the Albuquerque Journal reported.

Some lawmakers want the compact to resolve a dispute over “free play,” the complimentary spins a gambler receives. The state’s Gaming Control Board says tribes have underpaid tens of millions of dollars in state taxes because they don’t count wins on free spins as part of a player’s total winnings. Tribes are also concerned that the Navajos could revive an old plan to build a casino on Interstate 40, just west of Albuquerque, which would directly compete with several smaller locations nearby.

The Navajo Nation and four other tribes operate their casinos under gaming compacts that end in mid-2015. Nine other state tribes signed compacts in 2007 that run through 2037. The new Navajo compact would run until 2037.

New Mexico has a short legislative session in 2014, one that runs for only 30 days. The committee with jurisdiction over the compacts is expected to meet on Jan. 20, the day before the legislative session kicks off, to begin hearings on the proposal, state Rep. James Roger Madalena (D), told the Journal.

Tribes that operate casinos must report their revenue to the Gaming Control Board, but those numbers aren’t made public. In 2012, taxes on gaming revenue and winnings fed $68 million into state coffers.