Updated at 12:16 p.m.

Republicans dominating a nearly half-empty North Carolina House chamber held an unexpected vote Wednesday and managed to override Democratic Gov. Roy Cooper's veto of the state's two-year budget.

Republican leaders had spent months trying to persuade enough Democrats to meet the threshold for an override, and finally seized a moment when Democrats opposed to the budget weren't at their seats. The few Democrats who were on the House floor moments before the 55-9 vote erupted in protest, accusing Republican Speaker Tim Moore of tricking the chamber about the day's plans.

The override isn't complete — the Senate still must hold a vote on the issue, but Republicans there need only one Democrat to join them to secure victory. Senate absences also could make that easier.

"This is a tragedy. This is a travesty of the process and you know it," Rep. Deb Butler, a New Hanover County Democrat, yelled at Moore just before the vote began. "Mr. Speaker, how dare you, Mr. Speaker."

Moore told her that he "did not advise that there would be no votes this morning." Moore's office provided audio from Tuesday's floor session from House Rules Committee Chairman David Lewis saying recorded votes would occur Wednesday, specifically identifying two different spending measures.

The House budget override vote has been on the daily floor calendar since early July, and from time to time the Republican leadership had announced that there would be no recorded votes on certain days. There was nothing in the chamber rules to prevent such action Wednesday.

Wednesday's vote came as lawmakers have focused this week on redrawing legislative maps following a court ruling striking down dozens of districts due to extreme partisan bias.

It also marks the latest battle in a decade-long fight between Republicans who took over the General Assembly in 2011 and Democrats whose party had largely controlled state government for over a century.

Democrats have regained some power with Cooper's election in 2016 and 2018 legislative seat gains.

Cooper vetoed the budget on June 28, saying the two-year spending plan lacks Medicaid expansion for hundreds of thousands of low-income adults, contains paltry raises for teachers and unnecessarily gives corporations additional tax reductions. The veto and lack of an override had led to an 11-week budget impasse. Republicans have said Cooper won't negotiate unless Medicaid expansion is approved, too.

Cooper said he just wants the topic to be on the table.

Wednesday's vote was called quickly, giving dozens of Democrats little time to reach the floor. House Minority Leader Darren Jackson of Wake County also said that several Democrats who were on the floor didn't vote and were denied the chance to debate the measure.

Moore "kept talking over us. He turned off our mics," Rep. Mary Belk, a Mecklenburg County Democrat, said at a news conference. She and others went to other desks to use the microphones. As Butler and others continued to blast Moore's actions from the floor, the speaker threatened that he could order Butler to leave the chamber.

"The unseemly lack of leadership is incredible, absolutely cowardness, childishness," Butler said as Moore called for an override vote, on a separate Cooper veto, which also succeeded. That funding measure is needed to prepare for North Carolina's forthcoming shift to a Medicaid managed-care system. It doesn't contain any Medicaid expansion provisions, but Cooper said in his veto message that health care policy should be done comprehensively — a likely reference to expansion.