The Fire Brigades Union says it has still not officially been given details of plans released to the media and says the lack of negotiation shows that managers are "hell bent on confrontation".

Crews at Doncaster station will gather at a meeting tomorrow night, one of a series planned at stations across the county to guage feeling .

South Yorkshire Fire and Rescue is proposing that from early 2009, arrangements change from a nine-hour day shift and 15-hour night shift to 12-hour shifts for both days and nights.

South Yorkshire FBU Brigade chair John Gilliver said: "These plans came out of the blue despite national agreements about having 'no surprises'. There is growing anger from firefighters across the county at the threats to impose contractual changes without any negotiation.

"During last year's floods councillors and managers were applauding our commitment and praising our work. It is a disgrace that managers are now rewarding us by kicking us in the teeth. Managers are going out of their way to seek confrontation and not negotiation. They are behaving like dictators rather than professional public sector managers.

"I think the public will be disgusted at the way their firefighters are being treated. We are not looking for a fight, but we're not going to run away from one either."

The service claims the changes have been researched and will have significant benefits.

A spokesman for South Yorkshire Fire and Rescue said the FBU attended the initial meeting which started the project in March and had always been welcome to be part of the project team looking at shift systems.

He added: "No decisions have been taken and we are in a two-month period of discussion with the workforce. We are happy to consider any shift system which can achieve our aims, which include increasing productivity and time available for training, and we would like the FBU to engage with us to discuss the issues."