The Liquor Control Board of Ontario is encouraging people to stock up early for the first holiday weekend of the summer as unionized employees prepare to walk off the job.

"Customers entertaining [Victoria Day weekend] can avoid any possible service disruptions by shopping our stores early and stocking up," said LCBO senior vice-president Bob Clevely in a release.

In early April, LCBO employees voted 95 per cent in favour of a strike mandate. Workers could walk off the job as early as next Friday.

The Ontario Public Service Employees Union, which represents more than 7,000 LCBO workers, said key issues on the table are upgrades to health and safety standards, as well as boosting part-time wages.

"There is no reason for part-time workers to make less money performing the same work as full-time employees," said union president Warren (Smokey) Thomas. "There is no reason for part-time workers to go week to week without a schedule, and then only work a few hours."

The employees' four-year contract with the LCBO ended March 31 and Warren said the union is making preparations in case an agreement isn't reached before the May 17 deadline.

"To reach an agreement, the LCBO must address the inequities of part-time work," said Thomas. "So far, the LCBO is ignoring the glaring wage and scheduling issues for part-time staff. This is unacceptable to us."

OPSEU voted in favour of a strike mandate twice before during collective bargaining in 2005 and 2009. Both times a deal was reached before the deadline.

The union said that it would begin opening strike headquarters in London, Hamilton, Toronto, Peterborough, Ottawa, Sudbury and Thunder Bay next week. An additional 26 locations may also be opened going forward.

It would be the first strike in the LCBO's 87-year history if workers take to the picket line next week.