More than 400 workers at an art gallery in Ontario went on strike after union members voted to reject the museum's latest contract offer.

The Ontario Public Service Employees Union said in a statement that the offer failed to address key issues such as wage increases, protection for part-time workers, and outsourcing of jobs.

The AGO website said the institution was closed on Tuesday due to the work stoppage and management still hopes to reach an agreement through negotiations with OPSEU "soon."

The striking employees are members of OPSEU Local 535, including assistant curators, archivists, food and hospitality staff, researchers, teachers, carpenters, electricians, visitor services staff, among others.

The union accused the Attorney General's office of "shortchanging long-term dedicated employees with an offer that does not reflect contemporary wages" after 10 months of bargaining.

Paul Ayres, OPSEU local president, said in a statement on Tuesday: "We need a deal that helps us stay on our feet amid the cost of living crisis in the most expensive city in Canada — and the latest offer from AGO falls short of that."

The union previously said that part-time employees make up more than 60 percent of AGO’s workforce, earning an average of $34,380 per year.

OPSEU said in a statement earlier this month: "Meanwhile, most senior executives earn up to $200,000 per year."

Ayres said on Tuesday that public service workers "took a direct hit on their pay" during the COVID-19 pandemic and three years of wage restrictions imposed by the now-repealed Bill 124, which capped salary increases for public sector workers more broadly at one percent per employee per year.

Ayres added: "Being a 'world-class' institution, as the Attorney General's office claims, starts with being a decent employer."

He continued, "Last time we checked, part-time workers still pay full-time rent. We need a deal that allows you to earn a living and secure your future while working at AGO."