Services provided by Waterford City Council could be disrupted from next week because of a strike by general workers.
Some 135 Siptu members employed by the council are to take industrial action from Monday in a row over pay and allowances.
Among the services that could be affected are water, sewage, housing, roads, traffic, litter, libraries, open spaces, parks and cemeteries.
Siptu official David Lane said emergency cover would be provided, but this would be significantly below normal levels.
He said the union had served strike notice on the council over management's failure to conclude talks on bringing pay and allowances for manual staff into line with those in other local authorities.
Mr Lane said workers in other local authorities were earning up to 50 per cent more than Waterford city staff for performing the same duties.
Allowances were also a contentious issue. "For instance, employees in Waterford are paid a drainage allowance of only €48 a week for working in the city's sewers compared with €75 a week in Cork and Limerick.
"In some cases there are no allowances for using dangerous equipment such as chainsaws, although this is the norm elsewhere."
One of the "biggest discrepancies" was in the water section, which had "the lowest weekly pay rates in the country". Pay for manual operatives in Waterford was €500 a week, compared with up to €750 elsewhere.
He said from Monday pickets would be placed on all city council premises and other locations where the council conducted its business.
There was no one immediately available to comment at Waterford City Council.
