Finland has taken the "historic" decision to supply weapons to Ukraine following Russia's invasion of its pro-Western neighbour, the country's government announced Monday.

Helsinki will send 1,500 rocket-launchers, 2,500 assault rifles, 150,000 rounds of ammunition, and 70,000 servings of field rations, said Defence Minister Antti Kaikkonen.

"It is a historic decision for Finland," Prime Minister Sanna Marin told reporters.

Finland is a member of the European Union but not of NATO, although it does have partnership status with the US-led military alliance.