AUGUSTA, Maine — Democrats on the Legislature’s budget committee voted Wednesday to raise the cigarette tax by $1.50 per pack, going further than Gov. Janet Mills’ original proposal and revealing a centerpiece of their upcoming spending bill.

The party-line change would mark the first time Maine has raised that tax in 20 years. It would rise from $2 to $3.50 per pack of cigarettes with a corresponding hike in taxes on other tobacco products. It is expected to generate $111 million over the next two budget years.

That money will be crucial to a planned addition to the $11.3 billion state budget that the Democratic-controlled Legislature passed over Republican opposition in March. After doing that, lawmakers had only $130 million in projected revenue available to spend with $120 million of that earmarked for a budget gap in the Medicaid program.

It sent Democrats scrambling for more money to neutralize cuts to certain programs that Mills made in her January budget proposal and to fund new bills piling up in the State House. They turned to the tobacco tax that Mills proposed raising by $1 per pack in that original plan.

Public health groups pushed for the change by noting that Maine’s tax is the second-lowest in New England despite the state having a higher-than-average cancer rate. Matt Wellington, the associate director of the Maine Public Health Association, called it “a long overdue step that will save lives” and reduce cancer in the state.

Yet critics have noted the tax falls hardest on low-income people. Some Democrats banded with Republicans to kill a flavored tobacco ban last year. Convenience stores have led an aggressive lobbying effort against a tax increase, and conservatives were incensed after the committee vote on Wednesday.

“This is a tax-and-spend budget,” Rep. Ken Fredette, R-Newport, an appropriations committee member, said Wednesday night.

Democrats have taken several party-line votes on the budget in the appropriations committee this week. On Wednesday, they voted against Mills’ proposed cuts to child care subsidies. They have also opposed controversial ambulance and pharmacy tax increases in the governor’s original budget offer.

The budget panel expects to vote on the final budget early Thursday, Sen. Peggy Rotundo, D-Lewiston, the committee’s co-chair, said. The full cost of the spending plan won’t be known until then.