Portland’s controversial minimum-wage ordinance is set to take effect Jan. 1, but there are several unknowns about its enforcement.

Critics of Portland’s ordinance, which raises the basic wage from the state minimum of $7.50 to $10.10 an hour, say its language on enforcement procedures is too vague and could leave the city unprepared if it receives a flood of worker complaints after the ordinance takes effect.

The ordinance puts the city manager’s office in charge of enforcement, but does not include additional funding to hire a compliance officer, nor does it outline specific enforcement procedures.

The ordinance’s two-paragraph section on enforcement reads: “The city manager or his/her designee shall enforce the provisions of this ordinance,” and “The city manager is authorized to adopt rules and regulations for the proper administration and enforcement of this ordinance.”

It does go on to describe a procedure for workers to submit complaints about their employers, sets a fine of at least $100 a day per worker for employer violations, and gives the manager’s office 15 work days to follow up on complaints. The ordinance also grants underpaid workers the right to sue their employers in civil court to recover lost wages and attorney’s fees.

Maine Department of Labor spokeswoman Julie Rabinowitz said the section on civil litigation seems to indicate that Portland officials expect underpaid workers to fend for themselves in court.

“They’re letting it be a private right of action,” she said. “I have to say that concerns us.”

In 2014, the Labor Department investigated about 300 complaints filed by workers claiming they were paid less than minimum wage, Rabinowitz said. More than 100 of those complaints were determined to be valid, she said, although she did not know how many involved workers in Portland.

Rabinowitz said the state intends to refer all minimum wage complaints by Portland workers to the city beginning Jan. 1.

“We’re not going to turn anyone away, but we can only enforce the state statute,” she said.

City attorney Danielle West-Chuhta did not respond to questions Monday about the city’s enforcement authority.

Aside from unintended language that boosts the hourly wage for tipped workers to almost $7 by 2017, Portland’s minimum wage ordinance is comparable to those approved by other cities, with similar strengths and weaknesses. A Portland Press Herald review of nine other wage ordinances across the U.S. found that Portland’s falls somewhere in the middle in terms of its level of detail with regard to enforcement procedures, fines and underpaid workers’ right to sue.

Some cities’ minimum wage ordinances include detailed information about enforcement powers and procedures, and some do not, the Press Herald found. Seattle’s ordinance is the most detailed, while those of Los Angeles and Chicago provide even less information on enforcement than the Portland ordinance.

The Chicago ordinance contains a single sentence under the header of enforcement: “The department of business affairs and consumer protection shall enforce this chapter, and the commissioner is authorized to adopt regulations for the proper administration and enforcement of its provisions.”

Portland spokeswoman Jessica Grondin said it was premature to criticize the city for its lack of minimum wage enforcement procedures. The ordinance gives city officials the authority to develop those procedures before the ordinance takes effect in January, Grondin said.

“If they wanted to set up something more official, they could,” she said.

Grondin said Portland officials are not expecting to receive many complaints from workers in the city, because most already make more than $10 an hour. She said it is unlikely that any city employer is unaware of the minimum wage increase because it has been well-publicized.

If the new minimum-wage requirement does generate a significant number of complaints, there is a possibility the city would add a designated staff person to handle investigations, Grondin said.

One issue that has yet to be sorted out in Portland is the hourly base wage for workers who receive tips. The ordinance raises the tipped wage to $6.35 an hour as of Jan. 1, but city elected officials have said they had intended to leave it at the state minimum of $3.75, and that they plan to revisit the issue at next week’s City Council meeting.

In voting July 6 for the $10.10 minimum wage, the council also decided to increase it to $10.68 in 2017 and to tie future minimum wages to inflation.