The National Incomes Register (Kansallinen Tulorekisteri, KATRE) was introduced for salaries and benefits on 1.1.2019.The Incomes Register obliges every entity that pays wages or benefits to report the information to the Incomes Register. Benefits in kind will be included in the scope of reportable benefits when they have been made available to the employee.
If the employee is paid both a cash salary and benefits in kind, the information on both payments must be reported to the Incomes Register no later than the fifth calendar day. If the employee has not been paid a salary paid in cash at the same time, the information on benefits in kind can be reported on a monthly basis: however, the information on benefits in kind must be reported to the Incomes Register no later than the fifth day of the month following the benefit payment date. So, for example, a benefit in kind paid on January 15th must be reported by February 5th.
Read more about the income register on the website of the Tax Administration