When the City of Greater Sudbury unveiled a plan to modernize the city's fire service back in February, it was controversial from the start.

Many people voiced their opposition, including some volunteer firefighters.

Now, the union representing about 260 volunteer firefighters is accusing the city of punishing some of its members for speaking their minds.

"We're not being paid a whole lot of money, but we're still risking our lives like any other firefighter out there and I think it's important that our voice is heard out there," said Marc Morin, Christian Labour Association of Canada.

Some volunteer firefighters spoke out against the city's plan during public meetings, and some complained to their city councillors.

The union said the city is punishing those members with excessive disciplinary action and even termination in some cases.

"What the city has informed the volunteers is that comments made through social media, speaking to their councilors, being able to question or raise concerns during information sessions were off limits, which again we believe is inappropriate and wrong," explained Gord O'Coin, Christian Labour Association of Canada

With the fate of several volunteers hanging in the balance, hearings have been taking place for two days.

"I think it's clear the administration for Fire Service here has taken our comments very personally and it was never intended to be personal," said Morin.

"I think that they're being vindictive about their discipline at this point."

In a statement to CTV, the city said:

"We can confirm that members of the community safety department are being disciplined. This is a result of certain individuals' actions which violated City of Greater Sudbury employee handbook policies related to political and work communications. The City of Greater Sudbury respects the process it and the union have agreed upon in respect to disputes through the collective bargaining process."

The union said it will file a grievance against each one of the city's disciplinary actions against its members, and it will go to arbitration if necessary.