Supporters of play-or-pay rules argue that they keep employers from skimping on health coverage in an effort to undercut competitors that do offer health benefits.

Some types of employers, such as restaurants and temporary help firms, have argued that imposing any play-or-pay requirements on their businesses would jack up their costs, saddle them with massive new administrative burdens, and force them to cut back on the number of people they employ.

Others have argued that poorly designed regulations could make the play-or-pay provisions more burdensome than they would otherwise be or force employers to pry into workers' personal affairs.

Employer groups and insurance groups have suggested that some proposed play-or-pay interpretations could force employers to shift workers from one type of plan to another completely different type of plan every month.

The IRS has proposed several different methods that employers could use to classify workers and stabilize their benefits over the past few years.

In the Notice 2012-58, IRS officials create a "standard "measurement period" and an "initial measurement period" of 3 months to 12 months. An employer could use the hours worked during the measurement period to classify employees.

Officials also create a worker classification "stability period" that would have to be at least as long as the measurement period and could last from 6 months to 12 months.

An employer would have to look at a new employee after an initial measurement period and an "ongoing employee" after a standard measurement period. If the employer determined that the employee was a full-time employee, then the employer would have to treat the employee as a full-time employee in play-or-pay calculations throughout the coverage stability period.

For an ongoing employee, "the employer has the flexibility to determine the months in which the standard measurement period starts and ends, provided that the determination must be made on a uniform and consistent basis for all employees in the same category," officials say.

The safe harbor rules protect only employers that are offering eligible workers affordable coverage that meets the PPACA minimum essential coverage standards, officials say.

Officials also state that an employer can keep a new full-time employee out of the health plan for a 90-day waiting period without having to pay play-or-pay penalties.

An employer can use a 90-day "administrative period" to determine whether an employee is eligible for coverage and enroll an employee in coverage, but the administrative period "may neither reduce nor lengthen the measurement period or the stability period," officials say.

Using the safe harbor methods described in the new guidance is optional, and the new guidance will protect employers from having to comply with any more restrictive interpretations at least until Jan. 1, 2015, officials say.

Officials ask at the end of the guidance for comments on other play-or-pay interpretations that are still in the works.

Officials are asking about:

• The types of safe harbors they should develop for temporary employees and employees who fill high-turnover jobs.
• How employers and others should determine whether a new employee "is reasonably expected to work an average of at least 30 hours per week."
• The rules that should apply to mergers involving employers that use different rules for counting full-time employees.
• How they should define the term "seasonal worker" for purposes of applying the play-or-pay rules.

Comments are due Sept. 30.