The workers are represented by Local 508 of the Canadian Union of Public Employees and have been without a contract since December 2013.
They voted last month to give their union a strike mandate.
Union local president Kevin Smallwood says both sides recently resumed bargaining at the city's request but did not reach a deal.
Smallwood says the union was provided with the same package that it previously rejected.
He says benefits and wages remain outstanding issues.
The workers are responsible for variety of services, including water and sewage as well as street maintenance and cleaning.