TORONTO -- Issues with a new warehouse management system have delayed the delivery of booze to several LCBO stores, the provincial liquor agency said Wednesday as some customers complained about empty shelves and limited selection.

The Liquor Control Board of Ontario said technology updates at its Durham Retail Service Centre in mid-June caused some interruption in service and led to poor stock in a number of stores. It stressed that there were no supply shortages but acknowledged that deliveries were moving at a slower pace than usual.

The LCBO did not say when the issue would be resolved or how many of its stores have been affected.

"Our Retail Service Centre and any impacted parts of our business are working to minimize impact to our customers," it said in a statement.

The delays have prompted some outlets to post signs advising customers to ask for alternative recommendations to the missing products.

The president of the Ontario Public Service Employees Union, which represents LCBO workers, said his union has met with the agency about the issue.

Warren "Smokey" Thomas said the union has been given no information about when the problem will be resolved.

He said the agency is replacing a distribution system that had touted as the best in the world and he wasn't sure why it needed to be changed.

"When you switch computer systems ... sometimes it goes smooth, sometimes it doesn't," he said. "This one is not going smooth."

Thomas added that he hoped frustrated customers don't direct their anger over the delays at employees who are working hard to move product out to stores and fill shelves.

"It's not the fault of the people who are stocking the shelves or doing the deliveries," he said. "(The LCBO) took something that wasn't broken and tried to fix it."

Some customers have taken to social media to post pictures of empty LCBO shelves, saying they're upset about the delivery delays and lack of supply.

"Oh dear god no," wrote one Twitter user, posting a picture of a sparsely stocked shelf. "Booze shortage at the LCBO."

Another person tweeted that the delays were a sign of "astounding mismanagement."

"All GLCBO stores in Kingston have been short on booze for a few weeks," the user wrote. "Literally bare shelves throughout the stores."

The president of the Ontario Restaurant Hotel Motel Association said Wednesday that he's been in touch with the LCBO on behalf of his members, some of whom are being affected by the distribution delays.

Tony Elenis said with the summer patio season in full swing, restaurants and bars that order from the LCBO are sensitive to any delay in receiving product. While the LCBO has offered support, the situation could become problematic if the glitches at the warehouse remain unresolved, he said.

"Time is of the essence," Elenis said. "We're monitoring this very carefully. We're concerned if this keeps on for a period of time."