The federal government has weighed in to the bitter firefighters pay dispute saying it stands shoulder to shoulder with Victoria's CFA volunteers.

Prime Minister Malcolm Turnbull has written to Premier Daniel Andrews urging him to rethink his support of the proposed United Firefighters Union, News Limited reports.

And federal Employment Minister Michaelia Cash was in town on Saturday reiterating Mr Turnbull's view on the deal.

Fair Work commissioner Julius Roe came down on the side of the union in a hearing on Wednesday and issued non-binding findings the CFA says it cannot accept.

CFA volunteers say the recommendations fail to address their concerns about giving the union veto power over CFA operational and resourcing decisions.

But the union has hit back saying the findings dispel "untruths" about how the proposed enterprise agreement will negatively affect CFA volunteers.

A government spokesman said the government was still considering Fair Work's recommendations.

The CFA board is due to meet on Monday to consider the recommendations, but the government's decision could already be made by the time they meet.

The deal includes a "consultation clause" the CFA believes effectively hands the union a veto over management decisions.

Angry CFA volunteers will rally in Melbourne's Treasury Gardens on Sunday from 1pm.

Emergency Services Minister Jane Garrett is understood to be considering quitting cabinet because she strongly opposes the deal, which she has previously said would hand too much power to the union.

The CFA board and chief executive are also strongly opposed to the deal and it's understood they will refuse to sign it.