The National Conciliator has invited nurses' unions Tehy and Super to a meeting next Sunday in an effort to reach a resolution ahead of fresh strike plans.
The unions said they have issued a strike warning for the Hospital District of Southwest Finland.
The four-day strike is set to begin on September 6 at Turku University Hospital (Tyks), impacting surgery and intensive care units. The industrial action will affect all union members.
Tyks said the strike will lead to the cancellation of major surgeries. Patents will be transferred to other units, the district said.
The nurses' unions said they were also issuing a recruitment ban for the southwest hospital district as of Friday, remaining in force through the end of the strike on 9 September.
On Thursday the labour unions said they were planning to stage a walkout at Kanta-Häme Central Hospital in early September.
The unions said the strikes aim to put pressure on the state.
Super and Tehy have demanded a five-year salary programme in connection with salary increases, which would increase salaries by 3.6 percent every year for five years on top of the general salary bump.
In June, unions and employer groups settled a major municipal sector labour dispute. However, nursing unions did not participate in the negotiations, and announced they would continue their campaign for pay increases after the summer break, while preparing for a campaign of mass resignations.