The union rejected the latest offer from the employers' association, Visitas, Thursday night.
During the night mediators were in touch with the parties, who are still at loggerheads over a minimum wage increase. If an agreement is not reached, workers plan to go on strike Monday.
The union wants to see a US$ 83 dollar increase in the monthly salary, while the employers' association Visita will only agree to a US$ 69 dollar hike.
Eva Östling Ollén, president of Visitas, said it will be difficult to reach an agreement with the union.
"We have already compromised, and we have accepted changes along the way. So this feels very difficult. Very difficult"