The Virginia Senate and House of Delegates approved proposed changes to the current two-year budget, with Senate Democrats unanimously voting in favor of its version after changes were made that would set up a framework for the state to implement Medicaid expansion.

That language was absent on Sunday when committees in the two chambers voted on their proposals. Then, the vote in the Senate Finance Committee was split 10 to 5, with Democrats in lockstep opposition to the plan absent the possibility of expanding Medicaid.

Senate Finance Committee Chairman Walter A. Stosch (R-Henrico) told his colleagues that the proposal did not amount to a foregone conclusion on the future of Medicaid in the state.

“For those of you who are speaking against it because you believe it will result in the expansion of Medicaid, you’re wrong,” Stosch said. “For those of you who are speaking for it because you believe it will result in the expansion of Medicaid, you’re wrong — unless certain conditions take place that are subject to negotiation.”

On Thursday, a floor amendment with that language got them on board. The bill passed 36 to 4, with no Democrats voting against the plan.

“We should seize this historic opportunity,” Sen. John S. Edwards (D-Roanoke), said before the vote. “Up to 400,000 new individuals will be covered under this expansion. These people are too poor to buy insurance but make too much money to get coverage currently under Medicaid.”

Under the federal Affordable Care Act, states have the option to open their Medicaid programs to people with incomes up to 138 percent of the national poverty level — which is about $32,000 for a family of four — with the federal government paying the entire cost for the first three years. The federal share gradually declines to 90 percent.

Virginia would initially receive about $2 billion a year from Washington under the program. Gov. Robert F. McDonnell and others have been skeptical that Washington will have the money to keep their end of the bargain.

The spending plan the General Assembly is trying to amend runs through July 1, 2014, which would include the first six months of Medicaid expansion.

Senate Democrats, in anticipation of Medicaid expansion under the Affordable Care Act, touted the possibility of thousands of jobs and billions of dollars in revenue. But Republicans opposed to the idea continued to express concern that the federal government could leave Virginia holding the bag, forcing the state to cover the bill for hundreds of thousands of newly insured citizens.

“My fear and concern of the federal government’s ability to continue, as they stated they would, in matching this money in the expansion of Medicaid for the commonwealth of Virginia overrides what I know would be a great benefit to those living in my area,” said Sen. William M. Stanley Jr. (R-Franklin), whose district includes many lower-income residents.

Stosch’s amendment also proposed the creation of a fund that would collect any savings from Medicaid and could be used to cover costs in the event of a shortage in later years.

The House voted 74 to 22 to pass its version of the budget, after making minor changes to the plan approved by the House Appropriations Committee on Sunday. It did not add language to expand Medicaid in its version.

The House budget amendments also adds $15.4 million to fund Medicaid waivers, which allows people with disabilities to get services while living in a community setting rather than in institutions.

The House turned down a flurry of other floor amendments that members offered to try to advance causes that had failed earlier in the session.

Democrats proposed amendments intended to require that the state pay for the ultrasounds it mandated last year for women undergoing abortions, to prevent anti-gay discrimination by adoption agencies and state agencies, and to provide money to Planned Parenthood for breast and cervical cancer screenings. All failed.

Del. Robert G. Marshall (R-Prince William) had no better luck with his own raft of floor amendments, which aimed to make the budget a vehicle for proposals such as allowing college faculty to carry weapons and restrict abortion.

McDonnell unveiled his budget proposals in December. Both chambers must vote on each other’s amendments, then hash out their differences ahead of a final vote.

Laura Vozzella contributed to this article.