The holiday hiring frenzy is under way and robots are joining the rush to seasonal jobs.

Retailers and logistics operators facing a tight labor market are ramping up automation at warehouses for the holidays, when online order volumes can surge tenfold as consumers load up digital shopping carts in the weeks around Thanksgiving and Christmas.

To cope, some businesses are ordering up extra fleets of collaborative robots, or “cobots,” that use cameras, lasers and sensors to navigate warehouse aisles and lead workers to the right shelves or to shuttle bins full of products between workstations. Many are available for lease.

Rick Faulk, chief executive of Wilmington, Mass.-based Locus Robotics Corp., said demand for what he calls “surge robots” to bolster the armies of seasonal warehouse workers has grown this year, and the company is sending more than 500 of them to its logistics and e-commerce customers.

“We are seeing customers taking delivery earlier, and keeping the bots longer,” Mr. Faulk said, as retailers look to the machines for help in filling online orders and restocking the shelves at their brick-and-mortar stores.

France-based Geodis SA is boosting its robotic workforce by 75% to help workers at its U.S. warehouses fulfill fast-fashion orders during the holiday peak. This year the company, which plans to bring on between 6,000 and 7,000 human workers for the holiday period, is placing a total of 281 Locus units at five locations.

XPO Logistics Inc., which is hiring 20,000 human workers for the seasonal rush, is advancing its purchase of millions of dollars’ worth of robots the company expects to need next year so it can use them now to manage the spike in e-commerce orders.

“It’s a strategy for holiday peak that worked so well in 2018 that we’ve ramped it up this year and bought 30% more,” said company President Troy Cooper.

There aren’t broad industry figures on the numbers of robots in logistics operations, and most warehouses still rely largely on people pulling carts

or driving forklifts.

But scarcity of labor and the push for faster delivery are accelerating automation at warehouses. By 2025 about 27.6% of warehouses globally will deploy commercial robots, compared to around 3% in 2018, market advisory firm ABI Research estimates.

The companies are looking for help in the labor-intensive business of storing, sorting and packing goods for shipment, especially around the holidays, when retailers and logistics providers add tens of thousands of extra workers.

Delivery giant United Parcel Service Inc. expects to hire about 100,000 seasonal employees to support the anticipated increase in package volumes from November through January 2020. FedEx Corp. plans to add more than 55,000 workers, mostly in its FedEx Ground network.

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Automation companies say most of the seasonal demand for robots comes from customers that already use their units. That can make setup a matter of minutes or hours rather than weeks for new operations.

“Nobody is changing their operations the day before peak,” said Lior Elazary, chief executive of inVia Robotics Inc., which this holiday season is supplying about 200 robots to Rakuten Super Logistics, a division of Japanese online retailer Rakuten Inc. that used 40 units during last year’s peak.

The aging workforce is contributing to interest in warehouse robots, said Melonee Wise, chief executive of Fetch Robotics Inc., especially as companies look to fill gaps with temporary workers.

Many seasonal warehouse workers are over 55, she said. “They have back pain and knee pain, and not everyone is up for walking.” This year about 10 customers are using the company’s autonomous mobile units to fulfill peak-season orders for apparel, consumer electronics and heavy appliances such as dishwashers, she said.

Others say robots aren’t a universal panacea for peak-season pressure.

E-commerce logistics company Radial, which counts Cole Haan Inc. and World Wrestling Entertainment Inc. among its customers, uses robotics and automation at several of its fulfillment centers but says it isn’t ramping up those tools for peak. The company plans to hire more than 21,000 seasonal workers this year and says it has found scaling up the workforce is more efficient.

But with the U.S. unemployment rate at a 50-year low and businesses vying with Amazon.com Inc. and other big employers for workers, some operators hope robots can ease the hiring crunch.

“We’ve developed this collaborative model … because we just can’t find people,” said Mike Honious, chief operating officer for the Americas at Geodis.

A robot picks up a tote containing product at an Amazon Robotics fulfillment center . Photo: Paul Hennessy/Zuma Press

Write to Jennifer Smith at jennifer.smith@wsj.com