Reservists and National Guard members returning from the Persian Gulf should be able to get their old jobs back without trouble under a 51-year old federal law.

The Labor Department said it expects few enforcement problems.Government officials have received numerous reports about employers going out of their way to help the 222,000 reservists and National Guard members who left behind civilian jobs when they were called up for duty in the gulf.

Some businesses voluntarily made up the pay difference - the military jobs frequently paid far less than civilian jobs - while other companies continued to provide health benefits to reservists' families. Some businesses also gave reservists' families counseling services, the Labor Department said.

"There is every indication that most employers will be more than willing to restore jobs with no loss of benefits," said Labor Secretary Lynn Martin.

Under federal law, anyone called to military duty, or who volunteered for it, must be given their old job back if they meet certain requirements:

- They must apply for re-employment within 90 days of leaving military duty, or if injured, within 90 days of leaving the hospital.

- They must have left the civilian job for the purpose of going on military duty.

The veterans' re-employment rights law, in effect since 1940, requires employers to give reservists their old jobs back with the same seniority, status and pay, even if someone else was given their job while they were away.

Reservists continue building seniority while on military duty and may be entitled to a better job when they return. According to the law's "escalator principle," they step back into their jobs at the precise point they would have occupied had they remained on the job.

By the same token, this escalator principle works in reverse. If there were layoffs while the reservist was away and the employer can establish that the person would have been furloughed, the reservist would be placed on layoff status upon his or her return.

Returning reservists have certain protections against being laid off. The law says a reservist can't be discharged without cause for one year after his or her return. Companywide layoffs, however, are considered just cause and if the proper seniority rights were provided, reservists could still lose their jobs.

An employer must continue to provide all benefits to reservists while they are away, including pensions, pay increases, missed promotions, missed transfers and other benefits given for leaves of absence.