Massachusetts House Speaker Robert DeLeo is opposing a ballot question that would let the state issue a second slots parlor license. 

The Democrat said Monday that state lawmakers worked hard to pass a 2011 law allowing up to three casinos and a single slots parlor. He says passing a ballot question to allow an additional slots parlor would undermine that process. 

The question heading to voters in November would require the slots parlor be located near a horse race track. 

There are two horse race tracks in the state: Suffolk Downs, in Boston, and Plainridge Racecourse, in Plainville. Plainville was awarded the single slots parlor license created under the law. 

DeLeo says he opposes the question even though the additional slots parlor could benefit portions of his district in Revere.