Angry union leaders on Wearside are warning of a "winter of discontent" over plans which could see some city council salaries cut by £4,500 a year.

Sunderland City Council is amending pay scales following a nationally-agreed job evaluation exercise.

But while some will see a boost in their pay packets, others will face a staggered pay cut of up to 33%.

Unions are balloting on the city council's proposals, but union leaders are warning of possible strike action.

Along with other local authorities, Sunderland council has spent months carrying out job evaluations, designed to ensure staff receive equal pay for work of equal value.

Janet Greig, branch secretary of the GMB union, said: "There is a lot of discontent among the workforce regarding the amount of pay and size of pay cuts.

"The biggest losers will see a 33% cut, which after protection would be about £4,500.

"Our members have said to me that there will be another winter of discontent. They have said roads will not be gritted, not work overtime or weekends."

John Rawling, assistant corporate head of personnel at Sunderland City Council, said: "Our package of proposals involves three years of phased pay protection.

"We have a majority of union members who would win and would earn as gainers under this agreement.

"We also have comprehensive arrangements in our package of proposals to protect and modify the effects on any potential losers."

The result of the union ballot is expected by the end of October.