U.S. workers have some unlikely allies in the fight for paid sick days.

Rep. Mimi Walters, R-Calif., has sponsored a bill that would encourage companies to provide 14 to 20 days of paid time off — and Big Business loves it.

The bill would also encourage companies to allow for flexible work arrangements like job sharing or working remotely. On average, companies offer 10 days of vacation and 10 days of sick leave per year; the new legislation would lump all days off into one category, which would include sick time, vacation and holidays.

The bill would create a national paid-time-off policy for sick days and other personal needs, and businesses that comply would be exempt from tougher state and municipal rules. There are at least 40 different local laws designed to protect workers from being fired or disciplined for trying to follow doctor’s orders. About one-third of workers get paid sick days, either because local law requires it or their company offers it voluntarily.

“The problem really is the maze of state and local laws out there,” said Mark Wilson, chief economist at the HR Policy Association, the public-policy advocacy group for human resources executives at large U.S. companies, and a supporter of the bill.

San Francisco passed the first local paid-sick-day law in 2006. Connecticut passed the first state law in 2011. California and six other states have followed.

Most of the current local laws give employees the right to request sick days without notice, and employers can almost never deny them. The new federal legislation would allow managers to reject workers’ requests for time off.

Both sides agree that national rules would encourage more businesses to offer the benefit to part-time workers.