MONTPELIER — A Vermont House committee has approved a gasoline tax increase to take effect over two years.

The House Transportation Committee voted 10-0 with one member absent Thursday to approve a 2 percent sales tax on gasoline that would take effect in June. In July of 2014, the sales tax would go up another 2 cents on a dollar, to 4 percent.

Meanwhile, in fiscal 2015, the cents-per-gallon tax would drop by nearly 6 cents from its current level of 19 cents per gallon. The upshot would be nearly $26 million more in gasoline taxes collected by the state.

Lawmakers have been looking for ways to shore up transportation revenues. Declining sales of gasoline have cut into revenues from gasoline taxes that historically have been raised mainly on a per-gallon basis.