SALT LAKE CITY — A powerful group of about 100 Utah business leaders, education officials and former politicians kicked off a ballot initiative campaign Tuesday to ask voters to raise taxes to dramatically increase funding for public schools.

Supporters of the effort, including Utah Jazz owner Gail Miller and Zions Bank CEO and President Scott Anderson, say the increases could help address Utah’s overcrowded classrooms, teacher shortages and place among the lowest per-pupil K-12 education funding in the country.

The ballot initiative campaign, called Our Schools Now, proposes to raise Utah’s income tax and sales tax half a percentage point to generate $700 million annually. Income tax would go up to 5.5 percent, up from 5 percent. Sales tax would rise to 5.2 percent, up from 4.7 percent.

Critics, including Gov. Gary Herbert, say they worry raising taxes will hurt Utah’s economy and scare businesses away from setting up shop in the state.

Utah’s rate is already slightly higher than the rate in their neighboring state and rival, Colorado, and much higher than Nevada and Wyoming, which have no income tax.

But backers say businesses also care about operating in a state with a strong education system, which attracts employees and prepares future workers.

Anderson and former Questar chairman and CEO Ron Jibson said at a press conference Tuesday that they think Utah voters will approve the effort and pay a little more to help teachers and students.

Herbert, a Republican, has said that while he opposes raising the income tax, he thinks the Our Schools Now effort is good because it will put pressure on legislators to find other ways to generate money for education.

Shortly before filing the initiative petition with the state elections office Tuesday, organizers of Our Schools Now released details about their plan and the $700 million a year they expect the increases would generate — almost double the amount of new money Utah legislators sent to education this year.

About 85 percent of the new money would go to K-12 schools. The rest would go to public universities and colleges, including Utah’s technical school system. K-12 districts and schools can use the money for teacher pay, technology, early childhood education and other programs. Colleges and universities would be allowed to use the extra dollars for increasing the number of degrees and certificates handed out and graduate research, among other issues.

As required under state initiative petition laws, the campaign plans this summer to hold seven public hearings on the proposal throughout the state. If the state elections office approves the group’s application, including a check that the proposal is constitutional, Our Schools Now can start collecting more than 113,000 signatures they need by April.

Our Schools Now’s fundraising committee had about $90,000 ready to spend at the end of last year, according to their most recent state fundraising report. Early donor reports show an additional $106,000 in donations have come in this year — most of which came from a $100,000 check from Miller.