The Finnish Defence Forces (FDF) will send about 20 service members to Britain to assist in training volunteer members of the Ukrainian Armed Forces.
The UK has asked partner nations to provide support in the British-led training programme. It intends to provide basic military training to as many as 10,000 Ukrainian volunteers this year.
Senior Defence Ministry official Juha Martelius told Yle on Tuesday that so far Sweden, Canada and the Netherlands have announced that they will participate in the training.
The intensive training course will be carried out in Britain this autumn.
"The intention here is not to provide complete basic fighter training, but to participate to the extent that there is a competent group of trainers from Finland to meet the needs of the Ukrainians, and that are defined by Britain as the host country," said Martelius.
Britain began training volunteer members of the Ukrainian Armed Forces in July.
According to Martelius, the number of Finnish staff sent will be determined by Britain's request and by Finnish availability.
"The time period is quite short, and the number of trainers is not large enough to have an impact on domestic conscript training," he said.
Sweden has announced that it will send around 120 military experts as training support.
Finland and the UK signed a joint security declaration in May, just before Finland applied to join Nato along with Sweden. The UK Government approved the two countries' accession protocols on 6 July.
So far 21 of the 30 Nato member states have ratified the two Nordic countries' applications. Unanimous approval is required for membership.