Snowfall in late April or even in May is not unprecedented in the Nordic country.

There is even a Finnish word, "takatalvi", to describe instances of sudden cold spells making a return in spring.

However, the last time similar heavy amounts of daily snowfall were recorded in Helsinki on April 23 dates back to 1972 -- more than 50 years ago, Ville Siiskonen from the Finnish Meteorological Institute told AFP on Tuesday.

"Having this much snowfall in the south this late in spring is unusual, even exceptional", he noted.

A wide area of cold precipitation moved over Finland from the east on Monday evening, bringing freezing rain that quickly turned to ice as it hit the cold ground followed by heavy snowfall on Tuesday.

Eight centimetres (three inches) of snow was observed in Helsinki, and in other southern parts of the country the snow cover measured up to 20 centimetres.

"Major disruptions to public transport" were expected in the Finnish capital region the entire day, said the local authority managing public transport system in the Helsinki region, HSL.

Due to "ice on overhead wires following freezing rain", all tram services in Helsinki city centre were suspended.

Cancellations and delays were expected in rail and bus traffic.

Helsinki airport said the "exceptionally difficult weather" was causing flight delays.

"Runway de-icing and aircraft wing de-icing must be carried out much more than usual for the time of year" the airport said.

The snowfall was forecast to continue throughout the day but ease towards the evening, and temperatures would creep up over coming days, Siiskonen said.