Recycling and refuse collectors in Brighton and Hove are to ballot for strike action in a row over allowances.
The move followed two days of unofficial industrial action last week, which local newspapers report as having left uncollected rubbish around parts of the city.
Staff at the council’s Cityclean operation deal with recycling, refuse and street cleansing.
Their dispute follows an attempt by the council – the only one in the country to be led by the Green party – to change allowances paid to staff.
The GMB union said this would lead to “huge cuts to take home pay”, over which it had had “months of fruitless negotiation with council officers”.
GMB senior organiser Charles Harrity said: “GMB members at Cityclean have said enough is enough. They cannot and will not accept these vicious cuts to their take home pay.”
Harrity said council leader Jason Kitcat was “in an untenable position” as many Green party members supported the Cityclean staff, including the party’s only MP, Caroline Lucas, who represents Brighton Pavilion.
“The GMB does not embark on ballots for strike action lightly,” Harrity said. “However members now have no faith in Cllr Kitcat or his proposals.”
A council statement said it expected “some ongoing disruption to collections and street cleaning services across the city” following the unofficial action.
It said that hiring in extra staff and vehicles to catch up on missed collections was “not as easy as it may sound”.
“We employ over 100 staff who are out every day making recycling and refuse collections from 20,000 households. They use a fleet of more than 30 specialist HGV vehicles.
“Our staff know their rounds and are trained to drive and operate our recycling and refuse vehicles. Because of this specialist knowledge and equipment we cannot simply hire in agency staff and vehicles to catch up the missed work.”