PORTLAND, Maine — Labor and women’s activists have begun a campaign to win paid sick leave for all Portland workers.

On Friday, the Southern Maine Workers Center and Maine Women’s Lobby announced a proposal they’ve developed with Mayor Ethan Strimling and others to make Maine’s largest city the first municipality in the state to require employers to offer paid sick time.

The proposal, which will be formally announced at the Labor Day rally and presented to the City Council on Sept. 18, would require all businesses operating in Portland to let workers earn up to six paid sick days a year.

The local push follows the state Legislature declining to enact an earned sick time law in its last session, after the bill was opposed by business and hospitality groups. Proponents framed the proposed city ordinance as an opportunity for Portland to lead on an issue that affects public health, race and gender equity and the local economy.

“This ordinance really provides that basic safety net for families and for workers,” said DrewChristopher Joy, executive director of the Southern Maine Workers’ Center.

Eliza Townsend, executive director of Maine Women’s Lobby, said this was a chance for the city to demonstrate that “the sky would not fall” if all workers get paid sick time.

Under the proposed ordinance, workers in Portland would accrue one hour of paid sick time for every 30 hours they spend on the job, up to a maximum of 48 hours a year. The provision would apply to both full- and part-time workers, but would not affect employers that already offer this amount of sick time.

Although Portland would be the first city in Maine to enact such regulations, mandatory sick time policies are already in place in many other parts of the country, both far and near. Twenty-nine cities and seven states, including Massachusetts, Vermont and Connecticut, have such policies, according to a policy memo from Strimling.

But the proposed measure will likely be met with resistance by some of the same groups that lobbied against a bill proposed by Sen. Rebecca Millett, D-South Portland, which would have required Maine employers with 50 or more employees to provide up to 40 hours of paid sick time each year.

The Maine Innkeepers Association opposed the Millett bill, and the group’s director of governmental affairs said the local ordinance would likely be a burden on businesses, especially on smaller ones.

The statewide association will need to discuss the issue with its members in Portland before taking a formal stance, said Greg Dugal. But he also noted that the group has “traditionally opposed” paid sick leave regulations and called the Portland proposal a “Cadillac version” of such a plan.

The Maine Innkeepers Association and Restaurants Association, which also opposed Millett’s bill, together have 100 member businesses in Portland, according to Dugal. He said that, one way or the other, his group is likely to weigh in because of the importance of the restaurant and tourism industries in Portland.

Likewise, the Portland Regional Chamber of Commerce “will be working with businesses to determine the best path forward,” said Chief Executive Officer Quincy Hentzel.

A paid sick time ordinance was among the measures that Strimling called for in his January State of the City address. The mayor and Joy, of the Southern Maine Workers’ Center, said they are optimistic that the proposal will find support on the city council.

It is uncertain how many workers in Portland do not receive some form of paid sick leave. But as of 2015, there were more than 198,000 Maine workers who didn’t have access to paid sick days, according to the National Partnership for Women and Families.

After being presented to the City Council later this month, the proposed sick time ordinance is likely to be referred to the council’s health and human services committee, Strimling said.