Victoria's first-term government has been rocked by the prospect of losing its second minister in a year - this time over Premier Daniel Andrews' determination to push through a controversial deal that has outraged thousands of CFA volunteers.

After weeks of internal unrest, Emergency Services Minister Jane Garrett is considering quitting cabinet rather than accept an agreement that critics fear will hand increased power to the firefighters union, undermine the role of volunteers, and reduce the ability of the CFA to properly allocate resources.

Former minister Jane Garrett lost her job over her opposition to a workplace deal for paid CFA firefighters Credit:Simon O'Dwyer

Tensions over Ms Garrett's future mounted on Friday, after a cabinet subcommittee was hastily convened in a bid to ratify a proposal handed down by the Fair Work Commission earlier this week.

But the crisis engulfing the government is set to deepen even further on Sunday, when hundreds of CFA volunteers gather at Treasury Gardens for yet another protest over Mr Andrews' handling of the issue.