OLYMPIA — The Washington state House voted along party lines Tuesday to raise the state’s minimum wage — already the nation’s highest — to $12 an hour over the next four years.

The 51-46 vote sends to the Senate the bill to add a series of 50-cent increases to the $9.47 state hourly minimum wage. With Gov. Jay Inslee watching from the wings of the House, the bill drew extended debate in the Democratic-controlled chamber, and Democrats rejected a series of Republican amendments before voting to approve the bill.

The bill moves next to the Senate for consideration, where a companion bill did not get a committee hearing this legislative session. A coalition of mostly Republicans controls the Senate, and several have spoken critically of the effects a minimum-wage increase would have on the state.

Rep. Jessyn Farrell, D-Seattle, sponsored the House bill and said most workers who earn minimum wage now are adults and have a difficult time trying to stretch their pay to cover the expenses of maintaining a household. “If you work a hard day’s work, day in and day out, week after week, you should be able to pay your own way,” Farrell said.

She and other Democrats said a minimum-wage increase would boost the state’s economy by giving low-income workers more money to spend in their communities.

“This really is about strengthening the middle class,” said Rep. Pat Sullivan, D-Covington, the House majority leader. “It’s about making our communities stronger.”

Republicans countered that House Bill 1355 would cut profits and lead to higher prices and fewer jobs. Some businesses could be forced out of state or into closure by the increased cost of hiring Washington workers, several Republican critics of the bill said.

Rep. Matt Manweller, R-Ellensburg and the assistant minority floor leader, gave an impassioned criticism of the bill as failing to recognize basic economic principles. If it costs more to pay workers, he said, companies will hire less workers.

“How can we craft laws if some goods and services are subject to the law of demand and others are not?” he said. “Or is it, Mr. Speaker, that labor stands alone as the only good on the planet that is absolutely inelastic, because that’s what I’ve heard today?”

Under Washington’s current law, the minimum wage goes up every January with inflation. The Employment Security Department said this year’s minimum wage hike affected more than 67,000 workers.

By an identical 51-46 party-line vote, the House also approved a bill Tuesday to require Washington companies with more than four employees to offer at least one week a year of paid sick leave.