Unifor is taking dramatic measures to pressure Nemak to continue operating its Windsor plant.

Unifor National President Jerry Dias says the union is taking over the factory by establishing blockades at two entrances into the facility — and won’t be leaving until its collective agreement is honoured.

“This is about greed and we're not having any part of it,” said Dias as he addressed the gathered workers. “The CEO of the company has my phone number. I suspect he knows how to use a phone and we will be here until we have a solution.”

Both entrances have been barricaded with cars and union members while factory doors and equipment inside have been chained.

"Nemak cannot get away with betraying its workers or Canadians simply because they are motivated by corporate greed," said Dias.

The Mexican-owned aluminum casting plant, which builds engine blocks for General Motors, is expected to close in June, putting 270 people out of work.

Dias says members are holding the peaceful protest as a last recourse following a meeting with company head Armando Tamez last week in Mexico that produced no progress.

"We have a collective agreement where we've locked in product and Nemak, frankly, doesn't honour the collective agreement,” said Dias. “So if they're not honouring the collective agreement, then neither are we and we will be here until they change their mind."

In July, Nemak announced it planned to move production to its facilities in Mexico — Dias says that's a clear violation of an extension agreement signed with the union in 2016.

Workers walked out Monday morning shutting down all operations at the plant.

“There's only so many times you get knocked down before you got to stand up for your jobs. It's a shame that we still have to fight to keep Canadian jobs,” said Mike Jobin, the plant chair for Unifor Local 200.

Since 2015, Nemak has received $4.5-million from the provincial and federal governments to support the company's production in Windsor. The last of the payments from the federal government were completed in 2018.

Despite the public dollars, Nemak says it has to close the plant because a Chinese customer has dropped its order.

Speaking to CTV News after announcing the closure, Nemak spokesperson Louise Gaudette says the plant will be too under-utilized following the loss of the Chinese business.

"We recognize it's not easy for everybody,” said Gaudette. “You know, everybody is going to lose their job at some point here and we're going to try to make that transition as best as it can be.”

Unifor Local 200 president John D'Agnolo says the union will be at the plant for the long haul in the interest of workers.

"It's not like they make a ton of money here,” said D’Agnolo. “They've been here for a long time. They put their blood, sweat and tears into this site and they thought they had a future to the end of 2022 and these new programs coming and it's devastating to them. And that's why we're here.”

GM Canada responded to CTV News about Nemak.

“GM is aware that Nemak has made a difficult business decision to close their Windsor facility,” said spokesperson Jacqueline Thomson. “GM does not comment on its supplier’s business.”