TRENTON - New Jersey lawmakers in recent days have approved tax breaks for the film industry, investors in technology start-ups, senior citizens, and historic-preservation projects. They've voted to change how corporate taxes are calculated and to start a job-training program for the unemployed.

The reason, they say, is to jump-start the struggling economy.

But it could all cost roughly $500 million in lost revenue - and possibly much more - at a time when the state confronts a multibillion-dollar deficit in the coming fiscal year.

The proposals sweeping through the Statehouse are part of an effort Democratic legislative leaders call "Back to Work NJ" that was announced last month. They want to pass several dozen economic-recovery bills - some championed for years by business - for Gov. Christie to sign in January.

But some Trenton observers question whether the Legislature has done enough analysis on how to pay for the proposals and whether they will really create jobs.

"There is no way to pay for this . . . revenues aren't going up; there's not more money to spend, so if they're going to give tax breaks to corporations, they're either going to have to raise taxes on individuals, or they're going to have to cut even deeper into education and municipal aid," said Deborah Howlett, president of the New Jersey Policy Perspective, a nonpartisan, nonprofit research institute in Trenton.

Christie said Friday the bills' price tags and their impact on the state budget must be considered. Though he wouldn't declare his position on specific bills, the governor said his first job was to get the state's fiscal house back in order.

The nonpartisan Office of Legislative Services (OLS) projects an $11 billion state budget deficit next year.

The debate over the economic-recovery legislation highlights a difficult challenge for Christie, who wants to improve the state's poorly ranked business climate and lower the jobless rate - currently at 9.2 percent - while the state has little money to spare.

"There's no doubt about it, there would be an immediate loss of revenue," acknowledged Paul Sarlo (D., Bergen), chairman of the Senate Budget and Appropriations Committee.

"On the long-term side, you're hoping that the credits, the tax cuts that we're providing, and the incentives we're providing will ultimately stimulate the economy and create additional corporate business tax, sales tax, income tax," he added.

The most costly bill would consolidate certain business-related income-tax categories to allow people who receive money from different types of businesses to offset gains from one kind of business with losses from another. It also would allow companies to carry forward losses from one year for up to 20 years.

State budget analysts project the bill would reduce income-tax revenue by $375 million to $400 million next fiscal year. The Assembly Budget Committee approved the bill on Tuesday; Sarlo's committee voted for it last month.

Sen. Steven Oroho (R., Sussex), a sponsor, said making New Jersey's tax code more competitive would keep small businesses open and people employed, which would preserve the stream of individual income and sales taxes to the state.

Another bill that cleared the Assembly and Senate Budget Committees last week would restore and expand a film-production tax-credit program, which was cut in the current budget. The measure is projected to cost $45 million in forgone revenue.

Film-industry representatives have testified at length that the tax credits historically brought benefits that far outweighed their cost and provided numerous jobs.

The Senate budget panel also approved a bill Thursday that would provide tax credits for rehabilitation of historic buildings. Credits for homeowners would be capped at $25,000 per property over a decade, with no cap for businesses.

Supporters said it would create construction jobs, improve neighborhoods - and thereby property values - and bring New Jersey in line with 31 other states that have the program. The bill passed the full Assembly last month.

Officials in the governor's office have estimated the program would cost $15 million in the coming fiscal year, increasing to $50 million in 2015.

"Yes, you forgo some tax revenue, but you do that in the hopes of generating more than enough tax revenue in other ways, like increasing income tax, and increasing sales tax by purchasing construction equipment," said Sen. Majority Leader Barbara Buono (D., Middlesex).

On Tuesday, the Assembly Budget Committee approved a bill that would give tax breaks for investors in emerging-technology firms, which was projected to depress state revenue from $500,000 to $8 million a year.

The committee Thursday also voted for a measure sponsored by Senate President Stephen Sweeney (D., Gloucester) that aims to provide relief to senior citizens by exempting retirement income from taxes. The price tag: $62 million.

And lawmakers have appropriated $10 million for a key piece of the "Back to Work NJ" package, which would allow people receiving jobless benefits to receive up to 24 hours per week of work training with an employer. Last month, however, the OLS calculated that the total cost of the program should be less than $2.4 million.

Sen. Linda Greenstein (D., Middlesex), a sponsor of that bill, said in an e-mail that the OLS estimate may be too low, but that there was no harm in overestimating because the money set aside can revert to the general fund. She also noted that the Legislature has capped the Department of Labor's administrative costs to protect against spending abuses.

Contact staff writer Maya Rao at 856-779-3220 or mrao@phillynews.com.