BOSTON — A casino-financed group seeking to defeat a November ballot question to repeal the state’s expanded gambling law is ramping up its campaign spending.

The Coalition to Protect Massachusetts Jobs spent $702,000 from Sept. 1-15, according to the group’s most recent campaign finance filing. That’s up from the $577,000 it spent in the two months from its July formation to the end of August.

Among the expenses the group reported was nearly $190,000 in media buys through Boston advertising agency Conover Tuttle Pace. A campaign spokeswoman said those costs are for ads the agency produced that have run on local news websites and other mobile-driven sites.

The group also spent nearly $90,000 on forthcoming ads produced by GMMB Inc., a Washington D.C.-based advertising and media company that played a prominent role in Barack Obama’s 2008 successful presidential run and his re-election campaign in 2012.

The Coalition to Protect Massachusetts Jobs is financed largely by Penn National Gaming, which won the state’s lone slot parlor license and is building a $225 million development at the harness racing track in Plainville. MGM Resorts International, which won a resort casino license for its $800 million development in Springfield, also has been a major donor, as have a number of local labor unions.

If approved, the ballot question would effectively halt any casino developments from opening by repealing a 2011 law that allowed for the licensing of up to three resort casinos and one slot parlor in the state.

Meanwhile, Repeal the Casino Deal, the anti-casino group that is pushing for repeal, spent $50,000 in the same two-week reporting period. Much of that went to reimbursing loans and past expenses. The group raised about $36,000, leaving it with about $10,675 cash on hand. The largest donation ”“ $25,000 ”“ came from Linda Sallop, president and CEO of the Atlantic Charter Insurance Company.

By comparison, the pro-casino group had $506,429 left in its coffers at the end of the reporting period after receiving just one donation: $500 from the Springfield Chamber of Commerce.

The group did, however, receive non-cash, in-kind donations from the two casino companies. MGM Resorts reported $14,100 for providing rental space in Springfield to the group, and Penn National Gaming reported $4,441 for providing staff time and space for the group’s media events.

Much of the pro-casino group’s other spending in the two-week period went to its stable of consultants and campaign advisers, including the DCI Group, of Washington, D.C. ($43,772); Martilla Strategies, of Boston ($25,000); Campaign Industries, of Illinois ($22,816); O’Sullivan & Associates, of Boston ($20,000) and Kiley & Company, of Boston ($18,750).