Dozens of staff were sent home yesterday after a two-hour sit-in at Brighton and Hove City Council’s Hollingdean depot. Amid mounting tension, GMB union officials said it would be balloting its members on industrial action for the new year.

Refuse collectors said they were frustrated that they were not being listened to about problems with the new rounds, introduced in October, which had led to bags being left in the street sometimes for weeks at a time. Yesterday, for the first time, GMB officials attacked the changes that have brought chaos to the city’s collections. Mark Turner, branch secretary, said: “There is something fundamentally wrong with the new rounds. We are on a collision course with the council on this and something needs to be done.”

Seven of the city’s 36 crews left the Hollingdean Lane headquarters at their 7am start time yesterday. By 9am, 22 had gone back to work but 14 continued with the protest. After advice from the GMB that the action was illegal, the remaining staff agreed to start their rounds but were sent home without pay by Cityclean managers. The council has confirmed parts of the city had not received collections because of the dispute.

The controversial rounds were introduced to save money after the opening of a rubbish transfer station at Hollingdean. Up to 24 voluntary redundancies are expected as a result of this and new recycling rounds.

Yesterday, crews complained that collections were still up to two days late and planned changes to recycling rounds in February would add to the chaos.

Outside the depot, refuse collector Steve Wilson said: “We are being told we are not doing our jobs but it is other way round. If we are given realistic targets we will do our utmost to reach them. We are not the problem. It is the new rounds.” Colleague Runa Pradey added: “We do not want to let the residents down but the management are not listening.”

A council spokesman said: “No council would accept a situation where crews are choosing when to work. Refuse collection is a big issue in the city. Residents don’t like their service disrupted and this will be received very badly as we approach Christmas.

“There will be areas of the city without collections today. We’re asking residents to leave their bins and boxes out and we will collect them as soon as possible. If staff are not happy they can speak to the council directly or through their union.”

Brighton refuse collectors have a history of militancy, having successfully opposed changes to rounds in 2001 by occupying their depot (then run by a private contractor) and management harassment last year with a two-day wildcat strike.