Finavia is carrying out a programme of works in phases from 2014-2020, which it says is needed as traveller traffic is set to soar from its current 15mppa to 20mppa in the early 2020s.
Developments will focus on increasing check-in, transit travel capacity and improving traffic arrangements, all driven by passengers' expectations and air travel demand.
The first construction projects of new airport infrastructure are scheduled to begin sometime in 2015.
Finavia, says the aim of the development is to ensure that Helsinki Airport can maintain its strong competitive position in transit traffic between Europe and Asia.
Finavia's CEO, Kari Savolainen, says: "Passengers do not want any hitches and they expect quick transfers, high-quality services and a wealth of experiences.
"In a highly competitive environment, the success of an airport depends on these factors, and they must also be the focus areas at Helsinki Airport. One in every three passengers choose their flight routes on the basis of the transit airport."
The Finnish government is injecting €200 million into Finavia so it can get development work up and running.
Finavia says it will do its ‘utmost’ to minimise any inconvenience caused by the work and gave assurances extension of the airport after 2015 will not have any effect on the existing aircraft noise zones.
Changes made to the airport as part of the project are not expected to have any impact on the way runways are operated at Helsinki Airport.
Savolainen continues: "It is estimated that about 20 million passengers will be using Helsinki Airport in the early 2020s. This means that we need bigger facilities and that Helsinki Airport must be able to keep up with the demands and improve its processes.
"Maintaining our principal airport as a leading transit hub will ensure that Finns will continue to have extensive flight connections and it will also boost the competitiveness of the Finnish economy."
Rafts of improvements to the airport’s infrastructure are planned as part of the development over the next six years.
Terminal 2 is set to have additional security check capacity, a new congress area, and an automated check-in and baggage drop, which are all scheduled to be built in 2014.
Transit traffic capacity will also be improved with more spaces for wide-body aircraft in non-Schengen traffic.
The terminal could also be extended in stages sometime from 2015-2020 with the building of a satellite terminal, which would be built in accordance with demand.
The flow of departures and arrivals in Terminal 2 may also be improved sometime from 2017-2019 with the front of the building developed, and would be dependent on the timing of other projects taking place.
A single area for check-in, security control and baggage drop could be constructed and better transport arrangements introduced.
In addition to the programme, Finavia says it will also carry out repairs and maintenance work at Helsinki Airport, at important provincial airports and in air navigation services.
The upgrades will cost about €100 million and see improvements made to the paving of runways and terminal maintenance.