State lawmakers Tuesday tentatively agreed on a bill to deposit $200 million into the state Rental Housing Revolving Fund — the biggest single cash contribution ever for the fund — and to dramatically expand an excise tax exemption for construction of affordable rental housing to help cope with the severe housing shortage.

Lawmakers half-jokingly described House Bill 2748 as the “Bob Nakata Act” in honor of the former state senator and Rev. Bob Nakata’s years of lobbying and advocacy for affordable housing, and credited Nakata with pressing lawmakers to commit more public funding to fuel development of tens of thousands of units.

Nakata said he was initially skeptical the bill would emerge, because “it’s not an easy thing to get this many people together on something this large.”

The state, city and counties have “all pretty much stepped up and said this is something our people really need, and it needs to be done, and hopefully 30 years from now we will have made significant strides,” Nakata said at a news conference called to detail the agreement.

Senate Ways and Means Chairman Donovan Dela Cruz described the bill as a bold move because it will fund development of 25,000 units by 2030 for families that earn 140 percent or less of the area median income. The entire package including the general excise tax exemptions will provide an additional $570 million in public funding for affordable housing, he said.

The $200 million for the revolving fund is expected to generate approximately 1,600 affordable rental housing units for families. That funding is essentially used as gap financing by developers of affordable rental units to provide money that cannot be raised through private financing.

Currently the Rental Housing Revolving Fund has committed all but about $55 million of its available funding to projects that are planned or underway but is reviewing applications for about $200 million from the fund for about a dozen new projects, according to Hawaii Housing Finance and Development Corp. officials.

“What took place this afternoon will greatly help the cause,” said Darren Ueki, finance manager for the HHFDC.

The package announced by lawmakers Tuesday also includes $10 million that will be deposited into the Dwelling Unit Revolving Fund, which can be used to develop infrastructure for affordable-housing projects.

Another portion of the bill expands the general excise tax exemption for construction of rental units for families earning at or below 140 percent of area media income. Lawmakers estimate that tax exemption will encourage development of 24,000 new affordable rental units.

That excise tax exemption was created last year but was capped at $7 million per year. The expanded exemption is capped at $30 million per year, and the tax break was extended to 2030.

The excise tax exemption extension was requested by a group of developers and construction trade union officials who have been trying to assemble a package of incentives to encourage development of low-cost housing.

Richard Gushman II, CEO of DGM Group, said a group of larger landowners and developers came together to try to find ways to spark development of affordable housing, and a group of labor unions agreed to reduce their workers’ compensation by 15 percent for certain affordable-housing projects to jump-start the effort.

“The construction industry stands ready to build these units,” said Tyler Dos Santos-Tam, executive director of the Hawaii Construction Alliance. “We look forward to helping to produce more supply of affordable rentals to help solve our housing crisis.”

With that commitment from labor leaders in hand, Gushman said the developers agreed to accept significant decreases in rents for portions of their projects as their contribution.

From there Gushman met with banks to seek commitments to try to reduce financing costs for affordable- housing projects, and asked for and received similar concessions from architects and engineers. The excise tax exemption is part of the overall package, he said.

“There was no single- bullet answer,” Gushman said. “There was no one answer that changed the math for the whole thing.”

The newly amended version of HB 2748 will now go to the full House and Senate for floor votes.