Metro Inc. is seeking an injunction against striking employees who are picketing its warehouses and preventing deliveries to stores in Ontario, the grocer said Friday.

As the secondary picket lines continue for a third day, the union's actions are generating "significant" food waste, spokeswoman Marie-Claude Bacon said in a statement.

"We owe it to our customers across the province to ensure access to the food they need," she said. 

Workers started picketing two of the company's distribution warehouses on Wednesday, disrupting the flow of fresh products to the grocer's Metro and Food Basics stores across the province. 

The secondary pickets came midway through the fourth week of a strike by more than 3,700 workers at 27 Greater Toronto Area stores.

Consumers will notice empty shelves for certain products, namely produce, meat and dairy, at stores across the province, Bacon said in an interview.

"At some point it's going to be too late to be distributed in our stores and it's going to be wasted," she said. 

Secondary picketing is when striking workers picket at locations other than their own workplace. Unifor started doing this in the week leading up to the warehouse demonstrations at Metro-owned stores not included in the current dispute, Unifor national president Lana Payne told reporters on Wednesday outside one of the distribution centres. 

"Frontline grocery workers at Metro will continue their brave fight for decent work and pay over the weekend until the employer comes back to the table with a serious wage offer," Payne said in a statement Friday when asked about the grocer's request for an injunction. 

The injunction will be heard on Monday, meaning that's the earliest it could be granted, Bacon said. 

But it's not guaranteed that it will be granted, said Larry Savage, a professor in the labour studies department at Brock University. 

Though Metro called the union's blockage of the warehouses illegal, he said that's not necessarily the case.

Secondary picketing is legal and is protected by the Canadian Charter of Rights and Freedoms, but a court may deem it illegal if it involves what the court considers to be "wrongful action," which could include criminal conduct, Savage said. 

While Bacon acknowledged secondary picketing is legal, she characterized the round-the-clock blockade with no trucks allowed in or out as illegal. 

She said in the interview that Unifor has refused to agree on implementing a protocol for the warehouse pickets before the injunction is heard on Monday, one that might allow for some limited movement of products in the meantime. 

Payne called the warehouse picket lines "legal and necessary" in her statement Friday.

The request for an injunction is the latest move in what's been an increasingly heated week for the labour conflict between Metro and the striking workers. 

Metro on Wednesday said it filed an unfair labour complaint against Unifor, arguing the union wasn't bargaining in good faith by not returning to the table to negotiate. 

"The union should act responsibly and be at the table to discuss Metro’s offer," Bacon said in a statement Friday. 

Unifor, meanwhile, has said it's waiting for a better wage offer before it resumes talks. 

“If there is one group of workers who deserve respect, decent pay and decent work, it is grocery store workers in this country,” Payne told reporters on Wednesday. 

Metro workers have said they want to get their pandemic 'hero pay' of $2 an hour back in bargaining. 

This strike began after the workers voted down a tentative agreement that was recommended by their bargaining committee, one that the union described as their best in decades. 

That shows how central the 'hero pay' issue is to them in this fight, Savage said.

"Yes, it's about money. But more importantly, for these workers, it's about respect. Because having that pandemic pay yanked away sent a very clear message to those workers that their labour wasn't being respected."