Christchurch's city council is investigating back-up plans in case a pay dispute between rubbish collectors and their employer escalates.
Since Monday, the city's 50 rubbish truck drivers have been finishing work at 2pm, regardless of whether all the bins have been emptied.
The drivers want to be paid time-and-a-half for hours worked on top of an eight-hour shift.
Council acting manager of water and waste Tim Joyce said many residents had contacted the council, wanting to know why their bins were still full.
He said contingency plans were being investigated but the situation was manageable at the moment, and that if bins were not emptied, residents should leave them outside for collection the following day.
The workers will meet with their employer, Waste Management, tomorrow to discuss a resolution.