SACRAMENTO  (AP) — A faction of California’s largest union began submitting signatures Tuesday for a ballot initiative asking voters to raise California’s minimum wage to $15 per hour by 2021, one of two competing proposals vying for the November ballot.

Lt. Gov. Gavin Newsom joined SEIU’s United Healthcare Workers West in San Francisco as union officials turned in signatures. The group said it has collected 600,000 names, far more than the nearly 366,000 required to qualify an initiative this year.

The initiative, the latest in a nationwide effort by unions and other groups to raise the wage, would raise the state’s minimum wage by $1 a year starting in 2017 until it hits $15 in 2021. After that, increases would be automatically tied to the cost of living.

The cities of Los Angeles, Seattle, San Francisco, Oakland and Berkeley have approved phased-in increases to eventually take their minimum wage to $15 an hour.

The state council of SEIU also is collecting signatures for a competing minimum-wage initiative that would bring it to $15 by 2020, a year earlier, and provide six paid sick days annually. The union has pledged to spend $20 million to $30 million on a statewide campaign.

Lawmakers are also considering whether to attempt to pass a minimum-wage increase through the Legislature.

Gov. Jerry Brown, a Democrat, cautioned supporters during his budget announcement earlier this month that increasing the minimum wage to $15 an hour would cost the state general fund about $4 billion a year.

Business groups said the increase will be especially damaging to smaller operators and that the proposal raises wages too fast.

“While we know voters support some increase, this proposal to nearly double the minimum wage goes too far,” California Restaurant Association President Jot Condie said in a news release.

The SEIU state council has said it hopes both measures can eventually merge to avoid voter confusion and present a unified campaign.