AUGUSTA (NEWS CENTER Maine) -- Medicaid expansion was passed by voters two months ago. That law officially takes effect Wednesday, opening day for the second regular legislative session in Augusta.

Expanding Medicaid to thousands of more people is going to cost money. The question in Augusta is how much, and where will it come from?

The federal government will pay most of the cost of expanding Medicaid to tens of thousands of low-income Mainers, but there will also be a cost to state taxpayers. The exact numbers aren't clear yet.

The Legislature's fiscal office has estimated 27 million the first year, rising to 54 million when the program is fully implemented. Maine DHHS says 63 million to start, eventually reaching more than 90 million.

The Legislature's Appropriations Committee will have to figure it all out.

Democrat Rep. Drew Gattine is co-chair of the committee. He said, “Medicaid expansion is the law, I anticipate it will continue to be the law.”

Gattine said lawmakers need to get the program going this year, but won't have to come up with all the money right away. He said, “I'd like to see Medicaid expansion start as early as possible. From a practical perspective we probably don't need to appropriate additional money until sometime in 2019 but this session we need to figure out what those costs are.”

But Republican Jeff Timberlake, one of their top people on Appropriations, said “I would say this is probably going to be one of the toughest sessions on record in Maine.

Timberlake and a number of other Republicans and Gov. LePage all say lawmakers have to come up with the money if they want to expand Medicaid. And that it can't come from surplus or new taxes.

Timberlake said, “We need to tell the taxpayers of the state of Maine how we're going to fund it and pay for it before we implement it.”

He says lawmakers will also have to find millions of dollars for other programs. Including jails, the wait list for some disabled people, and direct care workers left out of the second year of the current budget.

It seems to guarantee that once again, money, how much and where to find it, will dominate the debate at the Statehouse.