Municipalities in Eastern Uusimaa agreed not to compete on pay for social workers, according to a report from the Swedish-language daily Hufvudstadsbladet.
"We have discussed pay and how we can ensure they are at the same level so that wages are not a reason to change employers," the paper reports Ann-Sofie Silvennoinen, who heads up health and social care in Porvoo, as saying.
The Talentia trade union says the deal amounts to a 'pay cartel'.
Sunday's HBL reports the union suspects that the agreement not to increase salaries was valid until the transition to new "wellbeing services counties", which are regional bodies that will take control of health and social care services in 2022.
Elections to new assemblies to run these regional authorities are scheduled to take place in January.
"At the same time as municipalities are making a lot of noise about a shortage of social workers, we have a large number of municipalities that are suspected of operating a social care worker pay cartel," said Talentia chair Jenni Karsio in a press release.
"I'm stunned, although we have heard rumours about these cartels."
Talentia says deals like this limit the free movement of labour. If there is evidence of an agreement not to compåete on pay, Talentia says it will take legal advice on getting it scrapped.