Small businesses are increasingly relying on part-timers and gig workers to meet holiday season work demands, but not all of them are happy about it, fearing potential regulatory and other issues.

According to a report from PYMNTs, there’s been a 37 percent increase in small- and medium-sized businesses’ hiring of gig workers over the last six months—more than any other type of worker—as business owners look for specialized professionals.

In a survey from research capacity building program Support of Competitive Research (SCORE), hiring increased across all categories of workers among small businesses; while gig workers accounted for 37 percent, part-timers saw an increase of 22 percent in the last six months and full-time employees increased by 13 percent. Most entrepreneurs, said the report, told SCORE that hiring had become a challenge as they try to fill skills gaps for their companies ahead of the holiday season.