Finland's military is tripling the number of reservists called up for refresher training courses, from 6,000 last year to 18,000 in 2015, a senior official said Friday.

Finland shares a 1,340-kilometre (830-mile) border with Russia, which is accused by the West of involvement in the war in eastern Ukraine. But assistant chief of staff Hannu Hypponen said the move was planned three years ago and was not related to the conflict.

"For the past three years the armed forces had an obligation to make savings... Now the number of refreshers has been put back to the level where it was in 2010," Hypponen told AFP.

"Around 2,400 employees were let go, allowing savings in staff expenses so that assets can be allocated for operational activities such as refresher courses," he added.

Hypponen admitted that while the restructuring began three years ago, the ongoing crisis in Ukraine has other implications for the military in Finland, which is not a member of NATO.

The Baltic Sea has recently witnessed an upsurge in Russian military activity which has prompted non-aligned Finland to announce closer military cooperation with its Nordic neighbours -- in particular Sweden but also with NATO members Norway and Denmark.

"Stepping up the readiness of the armed forces is linked to the situation in Ukraine," Hypponen said, referring to a recently-announced plan for a quicker call-up system for reservists.

Military service is compulsory for adult males in Finland, lasting between 165 and 347 days. Conscripts can later be called up for refresher courses lasting five to seven days on average.